Hydroids and Hydromedusae of Southern Chesapeake Bay

Home , Aglaura (hydrozoan), Bougainvillia, Campanulariidae, Cuninidae, Ectopleura, Hydroid (zoology)

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1971

Hydroids and hydromedusae of southern Chesapeake Bay

Dale Calder Virginia Institute of Marine Science

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Recommended Citation Calder, D. (1971) Hydroids and hydromedusae of southern Chesapeake Bay. Special papers in marine science; No. 1.. Virginia Institute of Marine Science, William & Mary. http://doi.org/10.21220/V5MS31

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LIST OF TABLES

Table Page Data on Moerisia lyonsi medusae ginia ...... 21 rugosa medusae 37

Comparison of hydroids from Virginia, with colonies from Passamaquoddy Bay, New Brunswick...... Hydroids reported from the Virginia Institute of Marine Science (Virginia Fisheries Laboratory) collection up to 1959 ...... Zoogeographical comparisons of the hydroid fauna along the eastern United States ...... List of hydroids from Chesapeake Bay, with their east coast distribution ...me...... O 8. List of hydromedusae known from ~hesa~eakeBay and their east coast distribution ...... LIST OF FIGURES

Figure Page

1. Southern Chesapeake Bay and adjacent water^...... ^^^^^^^^^^^^^^^^^^^^^^^^ 2. Oral view of Maeotias

inexpectata ...... e~~~~~e~~~~~~a~~~~~~~~~~~o~~~~~~e 3. rature at Gloucester Point, 1966-1967...... a~e.ee~e~~~~~~~aeaeeeeee~e 4. Salinity at Gloucester Point, 1966-1967...... se0me~BIBIeBIBI.e.BIBIBI.BIBIBIs~e~eeemeea~

LIST OF PLATES

Plate

Hydroids, Moerisia lyonsi to

Cordylophora caspia a a e..a a * a 111 ...... 113 ...... 115 ...... 117

...... 121 ...... 123 sae, Eucheilota ventric-

ularis to Cunina ~ctonaria...... ~ a o.a.ae ee 125

ABSTRACT

A survey was made in southern Chesapeake Bay and its tributaries from April 1965 through March 1968 to determine the species of hydrozoans present, their seasonality and reproductive periodicities. This report discusses 43 hydroid and 27 medusa species known from the study area, of which 23 hydroids and 11 medusae have not previously been found inChesapeake Bay. Clytia paulensis and the hydroid of recorded f OF records extend t and two medusae the southern

Carolinian Province than with the Acadian Province. The life histories of

require further life history studies to elucidate their generic and specific identity. Hydroids and hydromedusae were character- istically seasonalin occurrencedue tothe annualwater temperature range, varying from about 2 C in winter to 28 C in summer. Of 23 hydroids whose seasonality was studied in detail, 16 were "summer" species and seven were "winter" species, The seasonal occurrence ofthehydromedusae was typically less prolonged, with a maximum diversityinlate summer and early autumn, anda minimum diversity in winter.

HYDROIDS AND HYDROMEDUSAE

OF SOLITHERN CHESAPEAKE BAY

Dale R. Calder

INTRODUCTION

The Hydrozoa, a class in the phylum Coelenterata or Cnidaria, are characterized by having non-cellular mesoglea, tetramerous or polymerous radial symmetry, craspedote medusae, and ectodermally maturing gonads. The life cycle may include a polyp or hydroid stage only, amedusa stage only, ora metagenesis between the two. Thehydroidsare generallysessileand may be solitaryorcolonial. The medusae are usually solitary and free-swimming, A fertilized egg develops into a planula larva which settles and produces a polypoid phase or develops into the medusa without a persistent intermediate stage. Considerable synonymy has occurred in hydrozoan taxonomy because of polymorphism, Mayer (1910a) noted that much confusion arose because of the unfortunate practice whereby the medusae of an expedition usually went to one authority, the hydroids to another. Students of the plankton developed one system of nomenclature for the medusae, while benthic workers developed another based on the hydroid. Failure to appreciate the taxonomic significance of both stages is less prevalent now than in early work. Rees (1939) stressed that both hydroid and medusa must be given equal consid- erationfortaxonomicpurposes, and Russell (1953) attempted, where possible, to employ a unified system in his survey of the British Isles hydromedusae. On a worldwide basis, however, numerous life history studies are necessary before the problems of synonymy are resolved. The following history of North American hydroid studies, summarized primarily from Fraser (1944), shows that systematic study of North American Atlantic hydroids has proceeded with few interruptions since StimpsonPs (1854) synopsis of the marine invertebrates of Grand Manan Island, New Brunswick , Nevertheless, the work has been done by a relatively small number of scientists and few areas have been thoroughly investigated (Fraser, 1946). Early studies were made by Leidy (1855), Dawson (1858), McCrady (1857), and Packard (1863, 1867). Louis and Alexander Agassiz included the hydroids in their investigations but, according to Fraser (1944), their major contributions rested in their encourage- ment and support of marine research, the founding of the Penikese Laboratory and the Museum of Comparative Zoology at Harvard, and their association with the United States Fish Commission, all of which stimulated interest in marine life, including hydrozoans . Between 1870 and 1900, Verrill contributed a number of papers dealing at least in part with the Hydrozoa, and collections by various U. S. Fish Commission vessels were examined by Pourtales, Allman, Clarke, and Fewkes , In 1876 Clark reported briefly on New England hydroids, and in 1882 (as Clarke) published a paper on several Chesapeake Bay hydroids. Fewkes was active, particularly duringthe1880Ts, at various locations from Tortugas, Florida, to New England and Grand Manan Is land. Kings ley ( 1901, 1910 ), Whit - eaves (1872, 1901), and Stafford (1912) investigated the hydroids of boreal waters, while Versluys (1899)studied specimens from the West Indies region. During the early twentieth century, Nutting and Hargitt were the leading investigators, bJuttingfs (1900, 1904, 1915) monographs being particularly valuable, The Bermudas fauna was studied by Verrill (1900), Congdon (1907), Smallwood (1910), and Bennitt (1922), During the 193OPs, Leloup conducted a number of significant studies onAmerican hydroids. The studies of Fraser (1910, 1912, 1913, 1915, 1918, 1921, 1924, 1926, 1927, 1931, 1937b, 1940, 1941, 1943, 1944, 1945, 1946, 1947) represent the most significant contribution toknowledge of the hydroids and their zoogeography on this coast. His 1944 monograph summarized most of the known species and their distributionalongthe coast up to its publication date and is invaluable despite its obsolete systematics, In the two and a half decades since ~raser's(1944)monograph, systematic study of east coast hydroids has been largely neglected. However, a number of papers included the hydroids as part of a faunal survey (Behre, 1950 ; Bousf ield and Leim, 1960 ; Ferguson and Jones, 1949; Pearse and Williams, 1951; Smith, 1964; Whitten, Rosene and Hedgpeth, 1950). A few papers have discussed only one or two species of hydroids (Berrill, 1948; Calder, 1970a, 1970b; Crowell, 1945, 1947; Crowell and Darnell, 1955)- Since hydroids are of major importance in marine fouling, various fouling papers are a source of information (Calder and Brehmer, 1967; Cory, 1967; Fuller, 1946; McDougall, 1943; Weiss, 1948; WHOI, 1952) In the Gulf of Mexico and Caribbean Sea, systematic work has proceeded without interruption, with reports by Fraser (1947), Deevey (1950, 1954), Fincher (1955), and van Gemerden-Hoogeveen (1965). Recently, Vervoort (1968) reported on a collection from the Caribbean and included a check-list of the hydroids of the region, The works of Mayer (1910a, 1910b) represent the majorcontri- butions to knowledge of the hydromedusae of this coast, and his monographs included most of the previously published information, Bigelow in his various papers, particularly those of 1915 and 1918, added to knowledge of species along the mid-Atlantic. Sears (1954) summarized the species known from the Gulf of Mexico, Kramp's (1961) monograph included information onAmerican medusae published after MayerPsvolumes. In the last decade little has been published on the hydromedusae except for the work of Allwein (1967) at Beauf ort, North Carolina. Nothing of a comprehensive nature has been written on the hydrozoans of Chesapeake Bay since Clarke (1882) described f iue new species from the area, Cowles (1930) briefly discussed the hydroids taken from the offshore waters of the bay, but little information was given other than the species collected. Mayer (1910a, 1910b) included a number of medusae from the bay but did not conduct an intensive study. Consequently, little is known about the species of hydrozoans in Chesapeake Bay. The goals of this investigation were to identify the hydrozoans occurring in the lower bay and its tributaries and to determine the seasonal occurrence and reproductive periodicities of the more common species. Undescribedphases in the lifehistory of several species were completed by laboratory culture techniques, and the zoogeographic affinities of the fauna are discussed . It is a pleasure to acknowledge the assistance of Dr, M. L. Brehmer of VIMS for his counsel and provision of the equipment necessary for this study, Thanks are due the following hydrozoan specialists for their aid: Dr. Sears Crowell, Indiana University; Dr. P. L. Kramp and Dr, K. W. Petersen, Universitetets Zoologiske Museum, Copenhagen; Dr. N. A. H. Millard, Universityof Cape Town; and the late Dr. W. J. Rees, British Museum (Natural History), I am indebted to VIMS staff members D. S. Haven, R. Morales-Alamo, and We I. Sirnmonds for loan of equipment. Miss Evelyn Wells, VIMS librarian, is to be thanked for her assistanceinprocuring necessary literature. I am grateful to the following persons for providing specimens or aiding in their collection: Elizabeth Calder, Harold Cones, Jr . , James Feeley, James Greene, Sarah Haigler, William Johnson, Gail Mackiernan, Alex Marsh, James Melvin, Morris Roberts, Jr ., W. A. Van Engel, and Dr. M. L. Wass . Particular thanks are due to V. G. Burrell, Jr ,, for providing numerous specimens of hydromedusae and toR. Morales-Alamo for his large hydroid collection made during 1959-1961, The constructive criticisms of the original manuscript by Dr. J. D, Andrews, Dr. M. L. Brehmer and Dr- M. L. Wass of VIMS are greatly appreciated. Special thanks are extended to Mrs. Beverly Ripley for carefully and efficiently typing the final manuscript. This study was supported in part by contract NBy-46710 from The Bureau of Yards and Docks, United States Navy. The manuscript was prepared for publication at the Museum of Natural Sciences, National Museums of Canada, Ottawa, on a Postdoctoral Fellowship fromthe Nat5onal R~searehC~uncil of Canada. Fig. 1. Southern Chesapeake Bay and adjacent waters. MATERIALS A.ND ETHODS

To determine thediversity of hydroids in southern Chesapeake Bay, collections were made from over 50 different stations in the bay andits tributaries from April 1965 through March 1968 (Appen- dix A). Additional information was obtained from a hydroid collectionmade at Gloucester Point from1959 to1961 by R. Morales- Alamo of VIMS. Specimens and data from a fouling survey conducted inHampton Roads from May1964 until May 1966 were also used. This involved test panel surveys (Calder and Brehmer, 1967)and dredging operations at selected stations in the harbor. The region of study extended from the Rappahannock River on the north, southward to the Chesapeake Bay Bridge-Tunnel at the bay entrance, and included the Rappahannock, York and James river estuaries (Fig. 1)- Occasional collections were made on the bay side of Virginia's eastern shore. Collecting was undertaken at intervals of about one month at Hogge House Ground and Bowler's Rock on the Rappahannock River, Page's Rock and Bell Rock on the York River, and Nansemond Ridge, Middle Ground and Deep Water Shoal on the James River. Observations were made at frequent intervals, usually once or several times weekly, at a number of habitats in the Gloucester Point area. Dredging, manual collecting and divingwerethe principal methods usedincollections. Dredging was usually conducted from an outboard boat, although occasional collections were made aboard the R/V LANGLEY. Diving with and without SCUBA permitted --in situ examination and collection of specimens on submerged substrates. Test panels were employed as collecting substrates at Gloucester Point but no attempt was made to quantify the results. Most collected specimens were returned to the laboratory in water-filled containers and examined alive. This not only resulted in better specimens for identification but allowed for culture of hydroids whose identity was uncertain; in some cases medusae were necessary for specific or generic determination. In those species producing free medusae, hydroid colonies were usually isolated in large fingerbowls containing filtered seawater. The liberated medusae were examined or, if further rearing was necessary, were removed to jars or to petri dishes containing filtered seawater of a known salinity and maintained either in an air-conditioned room or a constant-temperature roomata selected temperature. Seawater was changed regularly, and medusae were fed Artemia nauplii or pieces of enchytraeid worms. Nematocysts were examined by dipping live specimens in dis- tilled water and staining with methylene blue. Weill's (1934) classification was followed in identification. All measurements were made with an ocular micrometer. Weekly plankton samples were taken fromthe east and west piers at VIMS from September 1966 through December 1967. A No. 20 mesh plankton net with an opening diameter of 11.5 cm was employed in collecting. The net was either secured to the pier and allowed to strain water during flood or ebb tide, or was pulled by hand for several lengths of the pier. Collections were examined alive or were preserved in formalin and examined later. As a supplement, selected samples in the VIMS plankton collection were examined, mainlythosefromthe entrance and southeastern regions ofthe bay. A collection of the hydromedusae previously sorted from the collections was examined as well. Allsalinitiesweredeterminedusing an Industrial Instruments 1nc.modelRS-7A inductionsalinometer. Temperaturesweremeasured by stem thermometers. The classification of salinityfollowedwas that of the Venice System (1958): E~haline~~~~~~~~...~~~~~~~~~.~~~~~~4O-3Oo/oo Mixohaline Polyhaline a~eee~~e~Be~OeeeBeOOO030-~8o/oo Me~0haline~.~~~~...~~~~~~~~~~~~~~18-5o/oo Oligohaline eae~ee~esseeeeBBOBee~5-Oa5o/oo Limnetic...... 8eBaD~OOlessthan 0,5 o/oo Original descriptions or redescriptions were made from living or freshly preserved specimens. Most other descriptions were made fromformalin-preserved specimens intheauthorPs collection. Draw- ings were made from photomicrographs or with the aid of camera lucida or microproj ector, TAXONOMIC ACCOUNT

A total of 56 species of hydrozoans, including 43 hydroids and 27 medusae (excluding juveniles and including Obelia spp. as one species) are reported for southern Chesapeake Bay in the following list. Two species, Eudendrium carneum, a hydroid, and Blackf ordia virginica, a hydr ed from literature Zinderwere identified from specimens examined during this survey. Eleven medusae and 23 hydroids are reported in Chesapeake Bay for the first time. The range given in this report refers to the North American Atlantic coast, and synonymies are given for Chesapeake Bay only. Representative specimens have been deposited in the Museum of Natural Sciences, National Museums of Canada, Ottawa,

Phylum Cnidar ia Class Hydrozoa Order Anthomedusae (Athecata) Suborder Capitata Family Moeris iidae Moeris ia lyons i hydroid & medusa Fa ri hydroid & medusa - medusa hydroid, no medusa produced Family Halocordylidae -- hydroid & medusa hydroid & medusa hydroid & medusa hydroid & medusa

hydroid & medusa

Family Clavidae Cordylophora caspia hydroid, no medusa ------produced Turritopsis nutricula hydroid & medusa Fa hydroid & medusa hydroid, no medusa produced Podocoryne minima medusa Fa eZ?E?T- Rdthkea octopunctata medusa Fa e ~ou~ainvilliacarolinens is medusa ------rugosa hydroid & medusa Garveia cerulea hydroid, no medusa produced Garveia franciscana hydroid, no medusa produced Aselomaris michaeli hydroid, no medusa produced Nemops is bachei medusa hydroid I medusa

hydroid & medusa

Eudendrium album hydroid, no medusa produced Eudendrium carneum hydroid, no medusa produced Eudendrium ramosum hydroid, no medusa produced

Order Leptomedusae (Thecata) Family Haleciidae Halecium gracile hydroid, no medusa produced Family Campanulariidae Clytia cylindrica hydroid hydroid, young medusa Clytia hemisphaerica hydroid hydroid hydroid, young medusa Obelia bicuspidata hydroid, young medusa Obelia commissuralis hydroid, young medusa Obelia dichotoma hydroid, young medusa Obelia qeniculata hydroid, young medusa Obelia longicyatha hydroid hydroid, young medusa Gonothvraea loveni hydroid, no medusa produced Hartlaubella gelatinosa hydroid, no medusa produced Family Lovenellidae Eucheilota ventricularis medusa hydroid I medusa F Opercularella pumila hydroid, no medusa produced Family Phialuciidae Phialucium carolinae medusa Incertae Sedis Blackfordia virginica medusa hydroid sp. 1 hydroid sp. 2 hydroid, young medusa Family Eutimidae Eutima mira medusa Fa riidae Dynamena cornicina hydroid, no medusa produced Sertularia argentea hydroid, no medusa produced Family Plumulariidae Schizotricha tenella hydroid, no medusa produced

Order Limnomedusae Family Olindiidae Maeotias inexpectata medusa

Order Trachymedusae Family Geryonidae Liriope tetraphylla medusa, no hydroid stage Family Rhopalonematidae ~~lanthadigitale medusa, no hydroid stage

Order Narcomedusae Family Cuninidae Cunina octonaria medusa, no hydroid stage

KEY TO CHESAPEAKE BAY HYDROPDA

1. Hydrotheca absent ~e~~ee~e~e~~e~e~~~~eBBDBDe~BeOOOOO~e~~a~(2) Hydrotheca present ~~~~~~m~~~~Qee*iO~~~eaBBe~~~~OO(D(D(De~e~~(23) 2. Hydranth with capitate tentacles .,...... Oe88eeeeeemmaOO(3) Hydranth with f iliform tentacles 0nly~.~..~~.~~..~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(7)

3. Hydranth with filiform and capitate tentacles e~~BO~s~~0OOOe~~~eO~BOOBi~e~eBBOmeeeeee~~~~~ee~e(4) Hydranth with capitate tentacles only 69e0~e00~~@OQOIDOe~~DDOB~eD~essOO~Beee@e~o~eme~~~~~a(5) Filif orm tentacles well developed, more than 4 in number, capitate tentacles in several regular

distal whorl^.,...... ,...^ ee OHalocordyledisticha Filiform tentacles reduced, 4 in number, capitate tentacles in

one distal wh~rl,...,,,..,....~ L) OODipurenastrangulata

Hydranth longer than stem, capitate tentacles short, scattered over hydranth, ..,,,..... ~~gO~e~o~OZancleacostata Stem longer than hydranth, capitate tentacles scattered

over hydranth ~~~~~~~~e~~~e80eBOBBesm~~~O~~OBDee~~e~e~~~~(6)

Hydranth c lavate, tentacles 10-20, scattered over entire hydranth, medusa with 4 tentacles developed at liberationeQB...0..8e~BeeBeee~~mODeBBBgg--Sarsia tubulosa Hydranth with a bulbous base bearing the tentacles, tentacles numerous, of ten 30 or more, medusa with 2 tentacles developed at liberation...... ~e~OeD~Be~~BBOOOOOOOOLinvilleaagassizi

Hydroids bilaterally symmetrical, with 2 tentacles only, commensal

with sabellid polychaetes a eProbos~ida~tylaornata Hydroids radially symmetrical, tentacles numerous eeeee~e~eem~plplBeL)BBe~BBOeaee~eOD~e~~m~(8)

Filiform tentacles scattered ~~~ee~eee~O~BeOeOme~eOB~em"ed(9) Filiform tentacles in one or more distinct wh~rls..,,.,.,,..,,~~~~~~~~~~~~~~~~~~~~~~(ll)

Colony regularly branched with well developed stem, annulations present, gonophores fixed o~OQeeemO~OOe8eBee~D~0eD~~OB(IOB8BO~~d~h~caspia Colony slightly branched or unbranched ~~eee~~e~eBBOBOBeBO~~~8~OO~D~m~~~@~e~~~~ee~~e(~o)

Perisarc thick, hydranth nutricula Perisarc thin, hydranth ~~ate~~~~..~.~~~~~~~~~~~~~~~~~~~~~~~~~~~Moerisialyonsi-

Tentacles in 2 clearly distinct whorls, proximal whorl larger and longer than distal,,, m~e~eoea~mOO~BBDeBOO~Oe810eBeeD(12) Tentacles either in 2 close whorls or a single whorl ~ee~oee~~~aaee~~OBsBO~em~eeBDea(13) Free medusae f~rmed..,~.~..~.~..~~~~~~~Ectopleuradumortieri Fixed gonophores formed, apical processes of gono-

phores laterally compressed.., Bea e @Tubulariacrocea

Perisarc about zooids very thin or absent, zooids arising singly from a stolonal mat ee~~e~~~~~~~~e~~~BBmBOeO~BeOB~~~ee~BO~eo~~e(~4) Zooids protected by thick peri~ar~.~~~~~.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(l6)

Zooids tiny (about 1 mm), tentacles about 16, web absent at base of tentacles ...,..,,,. Deme?tlCampanopsis"sp. Zooids several mm in height [email protected](15)

Tentacles absent on gonozooids, spines present, sporosacs

formed .O.B...e. eQBBsa~BeeBOeO~eeeli~sB~~Hydratiniaechinata Tentacles present on gonozooids, spines absent, degenerate medusae formed .....,....,.eBaDOBBOeeeBe~BDBHydra~ arge P

Free medusae formed ~~ee~~~~~~e@~O~eeOO~OOOO~BB~eD~DPO@~~(~~) Fixed sporosacs formed ~e~~~s~~~~~eeOe~(PD~e~~eOeBDBeBeeP1B(~8)

Stem polysiphonic, medusa buds borne on the hydranth pedicels, medusa with 3 tentacles in each cluster at liberation ...... ,. ....Bougainvillia rugosa Zooids arising singly from a creeping stolon, medusa buds given off from the stolon, medusa with 2 tentacles only

at liberati~n...... ,..~ eBeeeeee~BAhim dinema

Zooids arising singly from the ~tolon~~~.~~.~~~~.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(l9) Colony forming an upright stem with branches ~~~ee~~e~@~DeeBB~BODs~OBa~OBBBBBee~~e~~~~~(20)

Hypostome conical, sporosacs given off from hydranth pedicel only ...... e.,...eBBeeee~sO~OO~~e~~ma~i~ michaeli Hypostome trumpet-shaped, sporosacs given off from the base of the hydranth BOOe8eBOEudendriumalbum

Stem monosiphonic eee@~e~~Be~~B~e~Oee~BOBOO~BOe~eeeo~~~ea(2~) Stem polysiphonic, ~~eeeessaBeee8806eDee~~eeBe~a~e~meeeee(22) Each female gonophore with numerous planulae ...... 8.,,.eaBBeBm~BBBBeB~BGarveia - cerulea Each female gonophore with one planula ...,..,.....BBB~~m~eOOD~B. OOBGarveiafranciscana

Hydranths bright red, hydranths bearing gonophores ab~rted.....,...,..~Eudendrium carneum Hydranth whitish with red endoderm, hydranths with gonophores little or not ab~rted.....,..,...~~~~~~~~Eudendriumramosum

Hydrothecae free from stem, supported on a pedicel e~~~~~~~e~~~Beee~~OOe~mBDseB6)e~DD(24) Hydrothecae adnate on stem oe.~~~~ee~~~~seBeO~B~~OeOeeJ~B(41)

Hydrothecae saucer-shaped, not capable of covering hydranth, internodes long, stem straight ...... Halecium gracile Hydrothecae capable of covering hydranthBO.Be10.O.D0B~~e.e~.~c~OOOCCCeB~eee~~~~e~e~~e~~(25)

Hydrothecae campanulate, operculum absent ~e~e~~e~~~ee~~~Osc~B~OB8~~~eeBBbO~~e~~e(26) Hydrothecae turbinate or cylindrical, operculum presenteOQO..O.eBOOOB~D~eeeeOBOeeDO~sea~~~e~e~e~ee~e~~a(38)

Stolon network with pedicels upright, occasionally branched ; medusa free with 4 tentacles at liberation e~ee~e~o~ee~eeBseeOOeBe~eeOees~~e~~~ee~~ee(27) Stolon network with upright stems, medusae or fixed sporosacs formed...,~e.eO.eQ.e.e.e~eOee~O.ee~~~e.ee...e(3l)

Hydrothecal margin strongly pleated, hydrothecae 450- 540 p. long, 172-218 y wide, pedicel thine.O~.~OOQ.eeB.eeese.~~es~e~eOe.iee~~~Clti kincaidi Hydrothecal margin not strongly pleatedeOQ..O.P..O.eDe~e~OB~Oe~eOOe~eOO~~~mme~.~.~.eee~(28)

Teeth on hydrothecal margin bicuspidate, hydrothecae 410-600 p long, 140-180 p ~ide.~.~.~~~~~~~..~~~~~~~~~~~~~~~~~~.~~~Clytiapaulensis Teeth on hydrothecal margin ~timple~..~..~~.~~~~~~~~~..~~~~~~.~~~~~~~~~~~~~~~~~~~~~~(29)

Hydrothecae large, 750-1050 p long, 427-488 wide, teeth 10- 12, branching common, colonies up to 2 cm in height .....,...... e.Clytia edwardsi Hydrothecae distinctly ~rnaller...... ~~~~~~~~~~ 30, Teeth 7-10, hydrothecae 300-435 p long, 172-248 p wide, diaphragm thin...... BeneOaaClytiacylindrica Teeth about 12,. hydrothecae- 405-615 y long, 240-338 p wide, diaphragm thi~k...... ~ .. @Clytiahemisphaerica 31. Teeth on hydrothecal margin truncate, gonophores extruded into sac at top of gonangium ...... Gonothyraea loveni Teeth on hydrothecal margin bicuspidate, simple, indistinct or ab~ent~~~~~~~~~~~.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(32)

32. Gonophores producing fixed sporosacs, teeth about 10, each with a V-shaped indentati~n.....,..~~~~~~Hartlaubellagelatinosa Gonophores producing medusae with 8 or more tentacles at liberation.D..e00e.seO~BBBe~~DeeBBOOeO~Oea~~ee~~~~~~e~~(33)

33. Diaphragm very thick, stem geniculate, usually unbranched, pedicels very short, arising from a distinct internodal shoulder, hydrothecal margin entire0.e.08...... Bs~e~~.eOee~~es~~eeDeOObeliageniculata Diaphragm thin...... eos.eBa~~~e.eeeeOOeeeOee.

34, Hydrothecal margin wavy ~eD~.eeoe8eeeeeeeD~eDeeO~eeeeFeae(35) Hydrothecal margin entire or with bicuspidate teeth eeeee~.~~e~~~~OeOeeeee~DOBBB~Oees(36)

35. Colony large, 10.5 cm, much branched, hydrothecae 585-662 p long, 339-431 p ~ide...... ~~.~.~..~~~~.~.~~~~~~~~~~~~~~.Obelialongissima Colony small, 2.5 cm, little branched, hydrothecae 375-428 j~ high, 225-300 p ~ide.~~~~~~.~~~..~~~~~~~~~~~~~~~~~~~~~~~Obeliadichotoma 36. Hydrothecal margin entire, hydrothecae 285-428 ,LI high, 185-285 p wide, branches present eeeeOeeBeeeeBeOaee.D~eBeee~e~08eObeia c~mmi~~urali~ Hydrothecal margin with bicuspidate teeth...... s~e~De~OeOe~DOeeeDe~eese~~e~~(37)

37. Colony small (a few cm), hydrothecae 360-385 JJ. long, 188-210 p ~ide...... ~....~~~~~~~~~~~~Obeliabicuspidata Colony often large (up to 25 cm), hydrothecae 480-563 p long, 188-225 p ~ide...... ~....~~~~~~~~~~~~Obelia-longicyatha 38. Stem divided into short, cylindrical internodes by evenly spaced indentations, gonangia elongate, tapering gradually, several medusae per

gonangi~m~ oeaa a a a a- eLovenella gracilis Stem annulated or wrinkled,Be.0..80m000~OOO~e~OeDsOB

39. Opercular facets distinct, pedicels annulated throughout, occasionally branched, gonangia f~~if~rrn..~~~~~.~~~~~~~~~~~~~~~~~~~~~~~Opercularellapumila Opercular facets indistinct, perisarc wrinkled ~~~~~eeee@eBBieeeD80~OBee~Be~ee~0ees~e~(40)

40. Tentacles about 16, web absent at tentacle base, stem branched ...,....."Campanulina9' sp, 1 Tentacles 20- 219 web present at base of tentacles, gonophores each producing one medusa.., , ,,.,, ,.., ,."Campanulina7' sp. 2 41, Nematothecae present, hydrothecae on stem and branches, branching alternate, hydrocladia with (1) short internode lacking nematophores, node transverse at both ends, (2) longer internode, node transverse proximally, oblique distally, (3) thecate internode, node oblique proximally, transverse distally.. ,*. . ..Schizotricha tenella Nematothecae absent, hydrothecae adnate to stem and [email protected]~~e~~~eeeO~B~~eeBOeee(42)

42. Colony usually unbranched, small (5 cm or less), hydrothecae opposite, perisarcal projections from base, hydrothecae contiguous for half their length in front, well apart but parallel in back, gonangia oval, eeDynamena- cornicina Hydrothecae alternate, stem much branched, colonies large (up to 35 cm or more), gonangia arrow- shaped, one or two prominent shoulder spines., ...,...... e.BeBeeceODOSertularia argentea KEY TO CHESAPEAKE BAY HYDROMEDUSAE

Radial canals absent, margin divided into lobes, periphery

with 8 square pouches., ...... e Be eeBe eCunina octonaria Radial canals present, margin PP entireo..e.0.8800..eeOseeB~eOBODB~DOeOe~ee~ee~ee~ee~e~~e(2)

Ocelli present eee~~~~~e~e~~~BB000mOBBeO~08e(IIDmB~e~ee~~eee(3) Ocelli absent eee~~~ee~~~eee~aOe~BOOBeDO~OBeBOe~oe~~~~~~~(lO)

Oral tentacles present aeee~eaeeeemBO@~~~S@8ee@e~aeeOe~e~e(4) Oral tentacles absent ~e~e~ea~~e~eee(1eeB~eeOBe~OeeaeeOe~~e(6)

Oral tentacles unbranched, 3 marginal tentacles in each marginal cluster, ocelli typically fewer than marginal tentacles OQ...BBeOOB~eeDODD~~eBeBOB.~~eBougainvilliarugosa Oral tentacles branched...,.,..,..BeeD DOBe8~~eesaODB~0

Marginal tentacles all f ilif orm, gonads only on manubrium, oral tentacles with long base and divided up to 4 times ...... ,Bougainvillia carolinensis Tuo capitate marginal tentacles in each cluster, gonads extending along radial canal^...... ,...^ eNemopsis bachei

Marginal tentacles all filiformemeoeeaseeee..aeBeDBaeeeea(7) Marginal tentacles all capitate ~~ee~~~eee~eOe~B~eB~eP)e~Oe(9)

Manubrium simple, tubular, extending out of velar opening in ad~lt...... ~...~..~~~.~~~~~~~~~~Sarsiatubulosa Manubrium cruciform, lips present eeeO*e.~ee.eB~eCaD~~eeeBeeeaeOeeeeeeee*e~~ee~ee~e(8)

Endoderm cells above manubrium greatly vacuolated, mes oglea thin e..eBe.0.e.8.eeee~BeeeeeeeeO~~e~eeT~~p~~nutricula Endoderm cells not greatly vacuolated, mesoglea thick, gonads extending along radial ~anal~.~.~.~..~.~~~~~~~~~~~~~~~~~~~~~~~~~Moerisialyonsi

Manubrium tubular, extending out of velar opening in adult, gonad in 2 rings on manubrium...., ,....Dipurena strangulata Manubrium cruciform, swollen, not extending out of velar opening ~..e...... B~eOB~~Dee~.~eee~eL)eeeOLinvilleaagassizi Medusa with fewer than 4 marginal tentacles ea.@eeeeoae~DeDa@8aeBBB*BaeeaP~~@~a@e(ll) Medusa with 4 or more marginal tenta~le~.~~~~~.~.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(l2)

Of 4 tentacle bulbs, only one bearing marginal tentacles, marginal tentacles 1-3, apex rounded, umbrella somewhat asymmetrical ...... DI)~~~eOBOBO~O~~~~~BOeHybocodonprolifer Of 4 tentacle bulbs, 2 or 3 bearing one marginal tentacle each, margin with warts ...... BeBOBBAmph&ma -- dinema Medusa somewhat degenerate, marginal tentacles all rudimentary ~aeeee~eDee~eOOaeaeeB~.1.1DDDe~ee~~ee~~~~~~ee~(l3) Medusa well developed ~~~mm~@e~~~BDO~e~O~aO~OBO~B~~s~@ee~(~4)

Rudimentary tentacles 4....,...... 0...eHalocordyle disticha Rudimentary tentacles 8e.8.0...88ee08.e0 inia arge

Marginal tentacles with stalked nematocyst capsules, exumbrellar nematocyst tracks present .....,...... eeOOseeZanclea costata Nematocysts on marginal tentacles not stalked, exumbrellar nematocyst tracks present or absent. .eeee*~e~eeeOeaBeeeeaDDOe(15)

Eight meridional nematocyst tracks on exumbrella, manubrium simple and tubular....,.....Ectopleura dumortieri Exumbrellar nematocysts, if present, not in 8 meridional trackseO..eeeBeee.ee~OeOe~eee..ee~e~e8ee~s~eeeee~e~e~ee(~6)

Radial canals branched, primary radial canals 4...... ,...... 80.L1Proboscidactyla ornata Radial canals ~nbranched...... ~~~...... Statocysts absent .4,...... ,..,,...... (18) Statocysts present in the form of marginal vesicles or sensory clubs. ~~e~e~ee~~ee~Oe~~BeD~e~Oeeeee~eO~~~~ee(~~)

Four marginal tentacles, medusa buds on manubrium, gastric peduncle well developed ...... OeOs.eePodocoryneminima Eight tentacular bulbs each with 2-5 tentacles, medusa buds and gastric peduncle present ...... eeRathkea octopunctata 19. Velum rudimentary, medusa f lat, gonads round, tentacles numerous, 8 closed adradial marginal vesicleso...... ~B~BD~~~OB~BB~OOB~OeObeliasppO Velum welldeveloped,.. a~e~e~~aBeBe~eO~seD~B~sBBeOBe@~e~(20)

20. Manubrium considerably below velar opening on long gastric peduncle ~e~e~ee~e~e~eO~BDBDe~OOBOB)eBD~e@~e~e~e~(2~) Manubrium within subumbrellar ~a~ity~..~~~~..~~..~~~~~~~~~~~~~~~~~~~~~~~~.~~~~~~~~~~~(22)

21, Gonads 8, ribbon-like, along both peduncle and radial canals, marginal warts present, marginal vesicles 8, tentacles 4...,...... ,0~eB~eeeBBB~~~geEutimamira Gonads 4, leaf -like, tentacles 8....8.COP..0.BBOQ~BeCB~eDOBeBO~eOO~BeO~Liri0petetraphylla

22. Centripetal canals present, tentacles numerous, of one type, manubrium with 4 long frilly lobe~,...,,,.,..,,,~~~~~~~~~~~~~Maeotiasinexpectata Centripetal canals ab~ent,....~.,,.,.,~~~~~~~~~~~

23. Radial canals 8, elongate gonads 8, pendant from radial

canals near man~brium,...... ,~ e BAglantha digitale Radial canals 4, gonads attached along entire length ee~e~~eeeema~eDeeeBBeeBeeBe(24)

24. Lateral cirri present e~s~e~ee~ee~e~e~e~~BOe~Ba~BD~O~Os~e(25) Lateral cirri

25. Medusa large (up to 10 mm wide), marginal vesicles 8 with numerous concretions, qonads 4,...... ,.....,.e0 DeeeBeBEucheilotaventricularis Medusa small (up to 3 mm wide), gonads when young 2, later 4; marginal vesicles variable in number with few

concretion^.,....,..^^ ae.eBeeB eeBBam Lovenela gracilis

26. Gonads extending from manubrium along radial canals, marginal vesicles 1-2 between successive tentacle~....~....~~~~.~~~~~~~~~~~~~~~B1ackfordiavirginica Gonads along distal portion of - radial canal, marginal vesicles 4 between successive tentacles..,.,,...Phialucium carolinae Order Anthomedusae (Athecata) Suborder Capitata Family Moeris iidae

Moeris ia lyons i Boulenger, 1908 e 6, A

Moerisia lyonsi Calder and Burrell, 1967, p, 540.

Collection Records : James River--Hog Island, Deep Water Shoal. er--P-30,

Substrates: Plant detritus, Brachidontes recurvus shells,

Description: Stolon giving rise to oval zooids, about 1.3 mm high, 0,4 mm wide, girth maximal below tentacles in the mid-region, Tentacles arising 4/5 of the distance apically, extensible, to 2.5 mm, 4-10 in number, all f iliform. Frustule-like buds forming below tentacles, growing outward and constricting off to settle and develop tentacles.

Nematocysts: ~tenoteles..,,...,,~~~~~~~~~~8-12x 6-10 p (undischarged) de~monemes...... ~~~~~~~~~~~~6-8x 3-4 ). (undischarged) atrichous isorhizas , ,. . .7,5- 10 x 2,5-3.5 y (undischarged) Well developed medusa buds not observed but apparently given off near the base of the tentacles. Young medusae bell-shaped with 4 perradial tentacles and tentacle bulbs, diameter 0.5 mm, height 0.4 mm, manubrium short. Ocelli red, one per tentacle bulb, Radial canals 4, ring canal present. Nematocysts in rings about the tentacles, some scattered over the exumbrella, Mesoglea thin, velum broad, tentacle bulbs and manubrium cream-colored. Four interradial protuberances (precursors of interradial tentacle bulbs and tentacles) appearing in medusae of 0.7 mm diameter and height. Gonads developing in medusae of 1.1 mm diameter.

Nematocysts of young adults: stenoteles...... a eme Oe @8-12x 7-9 p (undischarged) desmoneme~.....,...~~~~~~~~7-8x 3.5-4.5 y (undischarged) haplonemes ...... ,.aeaa0aemsm~.7-9x 3-4 y (undischarged)

With increasing s ize, tentacles added continuously and diameter increased relative to height (Table 1). Manubrium small, quadrangular, perradial lips in large specimens occasionally crenulated, lips undeveloped in smaller specimens. Gonad surrounding the manubrium, extending outward along the 4 radial canals nearly to the ring canal, hanging down from the radial canals into the subumbrellar cavity, shape linear or slightly folded. Radial canals forming narrow median line, visible dorsally, along the entire length of the gonad lobes, Table 1. Data on Moerisia lyonsi medusae from the James River, Virgini ens captured during 1965 in a Clarke- Bumpus plankton sampler.

Collection Date Character Statistic 29-VII- 65 14-VIII-6 5

number specimens 2 5

Tentacle number mean mode range standard dev .

Diameter (mm) mean mode range standard dev .

Height (mm) mean mode range standard dev, Remarks : Moeris ia lyons i, the only known representative of the family Moe iEXrm America, was first reported from this continent by Calder and Burrell (1967). The specimens were found in plankton samples from low-salinity waters of the James and Pamunkey rivers, Va., during the summer of 1965. No specific search for M. lyonsi was made after 1965 on the Pamunkey River, but the specyes is evidently established and capable of survival in Virginia since medusae were collected in this study during the summers of 1966 and 1967 in the James River near Hog Island, Of the five presently recognized genera in the Moerisiidae, has more than one species, Distributionally, M. wn from Lake Qurun in Egypt and from Virginia, fl. 1 occurs in the Caspian Sea, and M. gangetica was describTd single specimen collected in thF Ganges rye Kramp considered from Japan a 9 and Odessia maeotic , Mediterranean, and c c oa Torrocco was placed in Moerisia by Naumov (1960), who resarded Ostroumovia inkermanica a? a synonym of M. maeotica. The status ofthe variouT'3EFZ~T~-speci .es is unceFta1"'n at present since the original description of M. lyonsi was inadequate and detailed taxonomic study of the qrozp ed , Identification of Virginia specimens as M. lyo6si has made by Dr. W. J. Rees of the British Museum (Naturaq Representative medusae from Virginia have been deposit e Universitetets Zoologiske Museum, Copenhagen, and in the British Museum (Natural History), London, as wellas the National Museum of Natural Sciences, Ottawa. The Moerisiidae were placed by Kramp (1938a) in the order Limnomedusae, having the following features in common with other representatives of the order: 1, Stomach quadrate 2. Tentacles hollow or with an endodermal core of more than one cell row 3. Tentacles with an endodermal root indicated Rees (1957), noting that morphologically the Moeris iidae resembled the Capitata, found also that the cnidome was capitate- like and, as such, unlike that of other Limnomedusae, Rees (1958) removed the family to the Capitata but erected a new superfamily, the Moerisioidea, for the Moerisiidae since he regarded them as more primitive than other capitate Anthomedusae. Naumov (1960) disagreedwithRees in transferring the Moerisiidaetothe Athecata because he regarded them as highly typical Limnomedusae, The Moeris iidae are retained here provisionally in the Capitata, although the systematic position of the family is still in debate, Moerisiid medusae are particularly well represented in the Middle East but have also been reported fromwesternEurope, India, Japan, Australia, North America and South America. This widespread distribution poses a zoogeographicalenigma sinceallbut two genera, eenfound onlyinlow-salinityorfresh ed that shipping was a possible means ica was introduced into the Nether- ~ingmoretolerantthanthemedusae, might survive in the crust of organisms on a ship's bottom, and once in favorable regions could produce medusae. Unfortunately, the range of temperature, salinity and other important factors tolerated by moerisiid polyps has not been precisely determined experimentally either in the laboratory or in the field. The hydroid has not previously been reported in North America.

Family Tubulariidae

Ectopleura dumortieri (van Beneden, 1844) -TB

Collect ion Records : Rappahannock River--Hogge House Ground. ErT -- sh Light, Gloucester Point, Pagers Rock, - Aberdeen Creek, ----James ~iver--Sewell%--- Point, Hampton Bar, Norfolk Navy Base Pier 12, Middle Ground.

Substrates: Rope, wood fouling rack, wire crab trap, fish nets, wood pilings, test panels (asbestos fiber, acrylic plastic), Halichondria bowerbanki, Crassostrea virginica shells, ETaTiiF-Trn~oEs- 1, ------Description: Zooids growing in clusters but arising singly from the stolons. Stem unbranched, reaching 26 cm in length but most much smaller, commonly 3-5 cm. Perisarc occasionally wrinkled, particularly toward the base, but annulations absent. Tentacles all filiform, in two whorls, about 30 distally and 25 larger, longer ones proximally. Gonophores producing free medusae borne onshort blastostyles arising between the two tentacular whorls. Medusa small (up to 2 mm high), nearly round, mesoglea relatively thick, exumbrella with 8 meridional nematocyst tracks. Tentacles 4, filiform, tentacle bulbs 4, of moderate size, ocelli absent. Radial canals 4, ring canal present, velum well developed. Manubrium simple, tubular, reaching to or approaching the velar opening, oral tentacles absent.

Remarks : The hydroid Ectopleura dumortieri is difficult todistin- guishfromcertain Tu --- ature, but when mature, medusae are producXFaTeT than actinulae, Hydroids were first identified in Chesapeake Bay by Dr. J. L. Wood of VIMS during October 1963 from specimens collected on rope suspended from a pier, The species was identified during this study on numerous occasions during 1966 and 1967. The hydroids were active from ApriluntilJanuary butshowedmarked seasonal changes inabundance. Colonies were common in spring, autumn, and early winter, being much less evident during summer. Additionally, most specimens collected during summer were small in size relative to spring and early winter hydroids. Medusae were common in plankton samples during autumn. The hydroid evidently thrives in the mesohaline environment of the lower river estuaries, and, on occasion, was collected in dense colonies. Fraser (1946) reported -E. dumortieri to be a small hydroid reaching little more than 1 cm in height, yet on 11 January 1967 specimens were collected which measured 26 cm in height. These hydroids were collected at a depth of 5 m from a gill net stake just below Bell Rock, York River. Examined colonies commonly measured 3-5 cm in height,

Seasonal Occurrence: Hydroid--early April through mid- January. --- -April through December. Known Range: Hydroid--Massachusetts to Chesapeake Bay. FI -Massachusetts to Florida,

Hybocodon prolifer L. Agassiz, 1862 -c

Collection Record : -Chesapeake Bay--station C-00, Description: Hydroid not seen. Medusa thimble-shaped but somewhat asymmetrical, about 2 mm high, 1.5 mm wide, apex rounded, mesoglea thin, Tentacle bulbs 4, 3 rudimentary and lacking tentacles, the fourth bearing 3 filiform tentacles and several developing medusa buds, ocelli absent, Radial canals 4, ring canal present, velum well developed. Manubrium simple, tubular, reaching nearly to velar opening.

Remarks: The record of this species is based on a single medusa taken in a Clarke-Bumpus plankton sample collected 29 February 1968 by V, G. Burrell, Jr. He prolifer is a boreal species not previously reported south of ~xawareBay where Deevey (1960) found it in February and April,

Known Range: Hydroid--New England. -Greenland to Chesapeake Bay.

Tubularia crocea (L, Agassiz, 1862) 'P C --Tubularia crocea Ferguson and Jones, 1949, p. 438, Collection Records : ----Chesapeake -Bay--Kiptopeke, Fisherman 's Island, pilings and islands of the Chesapeake Bay Bridge-Tunnel.

Substrates : Rock, concrete, wood pilings, Mytilus edulis shells. --- . Description: Zooids growing in tangled masses up to LO cm in height, stems unbranched, although hydranths occasionally developing at sites of injury. Perisarc frequently wrinkled and a few annulations sometimes present, but joints absent a Tentacles all f iliform, about 20-24 in each of two whorls, proximal larger and longer than distal. Actinulae produced in gonophores borne on long blastostyles frequently hanging below the tentacles, Mature female gonophores oval with 6-10 laterally compressed apical processes, radial canals absent. Malegonophores ovalor spherical, lackingapicalprocesses.

Remarks: The hydroids identified as T. crocea by Calder (1966) from Hampton Roads may have been ortieri since the preserved specimens from that stu 11's Point on 23September 1965, were subsequently found to be E, dumortieri. Data fromthat study have not been included here for eyther specles. Specimens of T. crocea were found in abundance during summer 1967 on the ChesapeZkeTy3ridge-Tunnel, particularly along the eastern quarter ofthespan. In August it was themost conspicuous hydroid on pilings at Fisherman's Island but was not collected in the York River and is evidently limited to the regionnear the bay entrance. Ferguson and Jones (1949) reported -T. --crocea from Norfolk but did not remark on its abundance.

Known Range: --Hydroid--Maritime Provinces to Florida and northern Gulf of Mexico,

Family Halocordylidae

Halocordyle disticha (Goldf uss, 1820) D ---Pennaria tiarella Calder and Brehmer, 1967, p. 153. Collect ion Records : York River--Perrin, Gloucester Point. r--Norfolk Navy Base Pier 12, Bay--Cape--- Charles. Substrates : Rope, wood pilings, asbestos fiber test panels, -----Zostera --marina. Description: Colony reaching 16 cm in height, stem monosiphonic, dark brown or black in the older portions, annulated at the base andabovethe origin of each branch, branches similarly annulated. Branching alternate, from all sides of the stem, branches also branched but not alternately, Hydranth clavate, with a proximal whorl of about 13 longtentacles considered filiform but showing a slight terminal enlargement, Two or 3 whorls of rather short and distinctly capitate tentacles occurring distally. Oval medusa buds borne just above the filiform tentacles on short stalks, becoming free, yet degenerate, medusae. Medusae elongate-oval, about 1.5 mm high, 0.75 mm wide, mesoglea very thfn, Tentacles and tentacle bulbs reduced, represented by 4 perradial knobs, ocelli absent. Radial canals 4, velum distinct. Gonads borne on the manubrium, manubrium simple, tubular, extending about halfway to the velar opening.

Remarks: During summer this hydroid is common to abundant on the eelgrass bed in front of VIMS at Gloucester Point. Hargitt (1900) noted that Ha disticha evidently occurs in two conditions at Woods Hole--an eaFl rockweed, piles, and similar substrates, usually in deeper water, and a later phase on eelgrass in shallow water. He was unable to find constant distinctive morphological differences between the two. The medusa, previously unreported in the bay, occurred in the plankton at Gloucester Point from June until early September. It was most common in plankton samples taken over eelgrass beds duringtheevening as the medusae are short-lived and are released from the hydroid in greatest numbers at dusk.

Seasonal Occurrence: Hydroid--early June through late October. -June through September.

Known Range: Hydroid--Massachusetts to the Caribbean Sea. -Massachusetts to Florida.

Family Corynidae

Dipurena strangulata McCrady, 1857 E

Dipurena strangulata Calder, 1970a, p. 109, fig. 1.

Collection Records : --York Rivey--Gloucester Point, Page 's Rock. Substrate: Microciona prolifera.

Description: Zooids of one type, arising singly from the stolon network, perisarc smooth, terminating slightly below the filiform tentacles. When extended, hydranth nearly tubular but short, reaching 0,8-1,Ommabove sponge substrate, maximum diameter 0.15- 0.20 mm at the distal end, 4 filiform tentacles in a proximal whorl and a distal whorl of 4-6 capitate tentacles. Capitate tentacles 0.2 mm long, 0.05 mm wide, with 8-11 endodermal cells. Filiform tentacles 0.15-0.17 mm long, 0.03 mm wide, occurring 1/3 of the distance apically. Terminal knobs of the capitate tentacles cone-shaped, 0.08-0,10 mm wide, silvery. Hypostome dome-shaped, the capitate tentacles usually extending above it,

Nematocysts : stenoteles large...... 20 6-25.0 x 14.4-18,2 p (undischarged) small...... ll8 9-170 2 x 7.9-11.3 p (undischarged) Medusa buds attached via a short stalk to the hydranth just distal to the f iliform tentacles, or on blastostyles, with a maximum of 2 medusa buds concurrently on a single hydranth. Just before liberation, marginal tentacles 4, well developed, tentacle bulbs 4, of moderate size, each with a single dark red abaxial ocellus, Velum broad, mesoglea thin, radial canals and ring canal present. Manubrium tubular, tapering from a somewhat bulbous base, a few scattered nematocysts on the exumbrella. Adult medusae (6-day-old laboratory-raised specimens) thimble- shaped, about 1,1 mm high, 1.0 mm wide, radial canals 4, fairly wide, velum broad, mesoglea thick. Marginal tentacles 4, terminating in a single knob, tentacle bulbs relatively large, each with a red abaxial ocellus. Manubrium simple, tubular, extensile, extending beyond the velar opening with as much as 2/3 or more of its lengthoutside the subumbrellar cavity. Gonads in two distinct rings about the manubrium,

Remarks : Although the medusa of D. strangulata is moderately well known, its hydroid was not describFd ly (Calder, 1970a), Hydroids were first observed on 18 June 1967, but the presence of medusa buds on specimens collected at that time suggested that the hydroid had been active for some time. Specimens were collected regularly at GloucesterPoint in depths from 1.5 to 4 m throughout the rest of the summer and reappeared in collections made 13 May 1968, During its observed interval of activity, water temperatures ranged from a high of 28 C toa low of 10 C, and salinities varied roughly from 18 to 24 o/oo, Medusae were first collected in plankton samples on 29 June 1967, and throughout the summer D. strangulata was one of the most abundant medusae in the samplesy

Seasonal Occurrence: Hydroid--mid-May through late November. -June through October,

Known Range: Hydroid--Chesapeake Bay, -Massachusetts to Florida,

Sarsia tubulosa (Me Sars, 1835) e 6, G

Collect ion Record : --York River--Gloucester Point. Substrates: Fiberglass wet table lining, Bougainvillia rugosa stems, Crassostrea --virginica shells, Description: Hydroids growingintangled colonies, stems unbranched or irregularly branched; 2 cm high, perisarc smooth or slightly wrinkled, hydranth elongate-oval, hypostome cylindrical, Tenta- cles capitate, scattered, 10-20 in number. Medusa buds borne on the hydranth just below the tentacles, Adult medusa thimble-shaped, about 2 mm high, 1,75 mm wide, radial canals 4, velum broad, mesoglea thick. Marginal tentacles 4, filiform, tentacle bulbs moderately large, each with a single ocellus , Manubrium simple,-. tubular, extensile, extendins cons id- erably beyond the velar opening andsterminating in a knob, Gonad covering the manubrium in an uninterrupted band from a short distance below its attachment to the mouth. Juveniles similar except the manubrium entirely within the subumbrellar cavity.

Remarks: The hydroid of this species was reported from the bay by Dr, W. G. Hewatt as Syncoryne mirabilis (Wass, 1965), but the record is suspect Hewattfs record was for August and S, in this area, were misinter- preted as S. since the two are s rphologically . south of New oucester Point during March 1966, Young medusae are difficult to distinguish from S. eximia as the manubrium is short and does not extend out ellar cavity, According to Russell (1953), young differ from -S. eximia juveniles in having exumbrellar In light of the medusa's known distribution, the records of S . tubulosa hydroids in tropical and subtropical waters are subject To tion. Russell (1953) stated that S. tubulosa was a circumpolar boreal neritic species. -

Seasonal Occurrence: Hydroid--late November through mid-May. -December through April,

Known Range: Hydroid--Greenland to Gulf of Mexico. Arctic Ocean to Chesapeake Bay.

Linvillea agassizi (McCrady, 1857) 6, F Collection Records : --York River--Gloucester Point, Page's Rock, Substrates: Cliona sp., Haliclona permollis, Microciona prolif er s odend Ha

Description : Stems unbranched, 1- 2 cm high, of ten obscured when growing among sponges, perisarc smooth, Hydranth with a bulbous base, hypostome very extensible, tentacles capitate, scattered, numerous, often 30 or more. Medusa buds borne among the tentacles, Young medusae about 0.5 mm high, thimble-shaped, mesoglea thin, radial canals 4, velum very broads Manubrium tubular, extending about halfway to the velar opening, Tentacle bulbs 4, opposite two bearing capitate tentacles, Ocelli present, one per bulb. Older medusae about 2 mm high with a large cruciform manubrium, pointed apex and 4 capitate tentacles,

Remarks: The generic name Linvillea was erected by Mayer (1910~) 0th of which were preoccupied. s similar to certain species ily distinguishable morphologi- tentacles at liberation, and There has been considerable confusion over this species at Woods Hole, where the hydroid has been confused for E. a 0 According to this errordated to E. ATas ) and A. Agassiz (1865) and was continued by subsequent writers (Murbach, 1899; Nutting, 1901; Hargitt, 1904)- In Chesapeake Bay, it was one of the more conspicuous capitate species, the hydroid reaching peak abundance in August and September, and the medusa during August,

Seasonal Occurrence: Hydroid--mid-May through mid-November. -June through September.

Known Range: Hydroid--Massachusetts to South Carolina. -Massachusetts to South Carolina.

Family Zancleidae

Zanclea costata Gegenbaur, 1856 e 6, H

Collection Record : --Chesapeake Bay--Fisherman ?s Is land. Substrate: Schizoporella unicornis, -- -- - Description: Hydroid minute, about 1 mm high, zooids arising singlyfromthe stolon, sessile orwith a very short stem, Hydranth elongate, bearing very short, scattered, capitate tentacles. Medusa buds borne below the tentacles near the base of the hydranth. Adult medusae not seen,

Remarks: This hydroid was found only once, on 29 August 1967 when it was collected on bryozoans adhering to pier pilings in 2- 3 m of water, At the time of collection, salinity was 23-95 o/oo and the water temperature was 25 C. Medusa buds were present on these polyps. The hydroid was not found on the same substrate collected fromwilloughby Bank and Gloucester Point and is possibly limited to the southeastern corner ofthebay where salinities are maximal, The two species included by Fraser (1944) for the Ameri- can Atlantic, -Z. -costata and -Z, gemmosa, are synonymous (Russell, 1953), Known Rang.e : .Hydr.oid--Massachusetts- to the Caribbean Sea, sa--Massachusetts to the Caribbean Sea.

Suborder Filif era Family Clavidae

Cordylophora caspia (Pallas, 1771)

Cordylophora lacustris Hyman, 1959, p, 316, fig. 12.2; Cory, -- .- 1967, p. 79.

Collection Records: Rappahannock River--near Tappahannock. er--near Indian Reservation. -- Fep Water Shoal, Lawnes Point, Hog Island Point, Jamestown Island,

Substrates: Rock, wood pilings, other C. caspia stems, --- Rangia cuneata, Crassostrea virginica sheTls7-

Description: Stem arising from a stolonadheringto the substrate, monosiphonic, sometimes appearing polys iphonic when providing substrate for other C. caspia colonies. Colony reaching 4.5 cm high, branching regular,an ons present basally onstems and branches. Hydranth clavate when extended, with scattered f iliform tentacles. Gonophores fixed, oval, arising from the stem or branches.

Remarks: The upper estuaries of the Chesapeake Bay system should provide a favorablehabitat for C, caspia since it is usually found in fresh or low-salinity watery ecies has been reported previously in the bay from Baltimore (Hyman, 1959) and from the Patuxent River by Cory (1967), where profuse colonies were found on test panels at Lower Marlboro. Cory observed attachment from JunetoOctober, with peak sets during June and July, In the pres- entstudyinsufficient datawerecollected to determine its seasonality, but colonies were observed during May, June and January.

Known Range: --Hydroid--Quebec to the Caribbean Sea.

Turritops is nutricula McCrady, 1856 I --Turritopsis nutricula Brooks, 1886, p. 388, plate 37. Collect ion Records : York River--Tue Marsh Light, Gloucester Point, Page % Rock. --Middle Ground. -Bay--Fisherman 's Island. Substrates: Haliclona ~ermollis,Halichondria bowerbanki,

Description: Colony branched ornnbranched, stems usually obscured by the sponge substrate. Perisarc smooth, terminating at the base of the elongate hydranths. Tentacles filiform and scattered. Medusa buds borne on short pedicels near the hydranth base. Adults thimble-shaped, up to 4 mm high, radial canals 4, velum broad, mesoglea moderately thin. Tentacles f iliform, numerous, closely spaced, tentacle bulbs relatively small, ocelli present. Manubrium cruciform, reaching nearly to velar opening, mouth with 4 lips bearing nematocyst batteries, endodermal cells above manubrium greatly vacuolated, Gonad developing in 4 segments about the manubrium.

Remarks: Brooks (1886) reported the medusa of T. nutricula from Hampton Roads, but contrary to Fraser (1944), he-fo roid only at Morehead City, North Carolina. The hydroid, reported in the bay for the first time here, was common on sponges throughout the summer in polyhaline environments of Chesapeake Bay. Medusae werecommonin plankton samples duringlatesummer and early autumn and were frequently paras it ized by actinulae of Cunina octonaria . -- ,-- Seasonal Occurrence: Hydroid--late May through late November. -August through October.

Known Range: Hydroid--Massachusetts to the Caribbean Sea, -Massachusetts to the Caribbean Sea.

Family Hydractiniidae

Hydractinia arge (Clarke, 1882) PRe 7, A

Sytlactis (sic) arge Clarke, 1882, p, 138, figs. 18-20.

Stylactis arge Mayer, 1910a, p. 151; Cowles, 1930, p, 330; 944, p. 83, fig. 59; 1946, pe 45, 138.

Collection Records: Rappahannock River--near Re 0. Norris Bridge. -- - Perrln,P Gloucester Point. Substrates: Enteromorpha sp., -Zostera marina, -Bittium sp. Description: Zooids of two types, gastrozooids and gonozooids. Gastrozooids arising singly from a hydrorhizal mat, capable of considerable extens ion and contraction, reaching 4 cm high but usually much less. Hydranth somewhat bulbous and rugose below the tentacles, hypostome club-shaped. Tentacles 14-20, all f iliform, extensible, occurring intwo closelyplaced verticils. Some gastrozooids showing adistalconstriction and stolonprocesses, hydranth and stolons eventually constricted off to form new colony. Spines absent, stolon network usually covered by periphyton. Defensive zooids absent, but resembled by zooids with autotomized hydranths . Gonozooids usually shorter and more slender than the gastrozooids, reaching 1 cm high, Tentacles 4-13, hydranth base not bulbous or rugose. Medusa buds developing 3/4 of the distance apically, usually 4 buds developing concurrently but occasionally as many as 10 present, Sexes separate. Medusae degenerate, with 8 vestigial tentacle bulbs, 4 radial canals. Brownish manubrium extending 3/4 of the distance from apextovelar opening, Medusae 0,8 mm high and wide at liberation, approximately triangular in outline, mesoglea very thin, velum present, Gonads forming a ring about the manubrium, fully developed before liberation, gametes released within 2 hours after liberation under laboratory conditions, medusae short-lived, none living longer than 12 hours in the laboratory.

Remarks: This species was placed in the genus Hydractinia on the basis of studies by Kramp (1932), who showed tha merits no more than subgeneric rank, Evidencefromlaboratory-maintained colonies and from plankton samplingatdifferent hours ofthe day suggests that Ha arge medusae are liberated in greatest numbers at dusk, ~his-'pFe=menon is also seen in rdyle distichs, H. arge y Clarke (1882) from Crisf ield, Mary lZndFE5 es (1930) did not collect it in his faunal su ay but stated that it was known from the Fort Wool region. While several of Clarke's hydroids were found at Fort Wool, H. was not, and Cowles' report is evidently in error since no rence to another record of the species was given. It was listed by Fraser (1944) only from its type locality. Thus, the present report constitutes the first Chesapeake Bay record since Clarke's description, Fraser (1944) believed there was little difference between H. and the better known H. from Long Island Sound and We land. He believed MZy a) had seen these species, but Mayer did not claim to hav arge and only related the characteristics listed by Clarke (18g2)rA critical comparison between the two species has not been made, and specimens of H. could not be located during this study for comparisoE. ecies should be retained pending a thorough comparison of and determination of possrEble character variation and overlap. Present knowledge suggests H. arge is distinct from H. in having longer gastrozooids, -no Y__4 splnes, a double row Zf es, and the occasional presence of stolon-like processes and a constriction at the distal end of a zooid. Should the two subsequently be found synonymous, the name H priority over H. described by SigerFo medusae of botT a erate and inseparable resent descriptions alone. Crowell(1947)discussed a Hydractinia of uncertain systematic pos-ition obtained at Woods Hole ed that it might be H. arge, a new species, or specimens illustrating the variation witr- PIn a single species, Like H. his specimens lacked spines, had tentacles in two verticiys, bore medusa buds about 3/4 of the distance apically. The only basis for regarding it as a new specieswasthe reported presence oftentaculozooids, notpreviously reported in either H. arge or H. These tentaculozooids may have been gastroz ized hydranths, commonly observed in H. arge co no typically H. hooperi characteristTcs~ntioned and Crowell's hydroid does not- to illustrate overlap of characteristics between H. hooperi and H, as suggested, His specimen is interpreted heTe ZsTTcord Of - -rge, the first such report outside Chesapeake Bay. Seasonal Occurrence: Hydroid-- late May through early December. FT -June through September,

Hydractinia echinata (Fleming, 1828 )

Hydractinia echinata Clarke, 1882, pa 14, fig. 40; Cowles, 1930, Pe m; 1944, p, 78, fig. 55; Ferguson and Jones, 1949, pe 438; Calder and Brehmer, 1967, p. 153,

Collection Records: York River--Guinea Neck, --Norfolk Navy Base Pier 12, Bay- -New Point Comfort, Cape Charles, Kiptopeke Beach, Fisherman 's Island.

Substrates: Wood pilings, asbestos fiber test panels, Crassostrea virginica shells, gastropod shells inhabited by -s and -P. pollicaris,--- --Balanus eburneus Description: Zooids of two types, gastrozooids and gonozooids. Gastrozooids arising singly from stolons, very contractile, cylindrical with a conical hypostome. Tentacles filiform, in a more or less distinct whorl, varying greatly in number, spines present, large and jagged, Gonozooids shorter than gastrozooids, tentacles lacking, apex capped with a bulb of nematocysts. Gonophores fixed, borne about midway on the gonozooids, 3-6 in number,

Remarks: H. echinata was common in polyhaline waters of Chesa- peake Bay 7% nhabited by hermit crabs, At Guinea Neck and ish her man's Island, large colonies covering several dm2 were observed on pilings and shells. Clarke (1882) reported it in abundance from low water to the bottom on certain wharf piles at Fort Wool, Virginia. Known Range : Hydroid--Labrador to Florida and northern Gulf of Mexico.

Podocoryne minima (Trinci, 1903)

Collection Record : --York River--Gloucester Point plankton sampling station. Description : Hydroid unknown. Medusa bell-shaped, about 1 mm high, radial canals 4, velum well developed, mesoglea fairly thin, Tentacles 4, filiform, arising from 4 tentacle bulbs, ocelli absent. Lips 4, perradial, tentacle-like and knobbed terminally with nematocysts. Gonads or medusa buds arising from the manubrium, manubrium borne on a short gastric peduncle.

Remarks : This medusa was recently found in North America by Hopkins (1966) from Florida and by Allwein (1967) from North Carolina. This Chesapeake Bay report is the first record of the species north of Cape Hatteras, A closely related species, P. minuta, is also known from Beaufort and Florida but was not co'Te- in Chesapeake Bay. The principal difference between the two medusae is the number of marginal tentacles, P. having eight and P. ' ' four. Russell (1953) believed-th sequent study mighT s minuta tohave four tentacles early in development and that theDtw be conspecific. Vannucci (1966) noted that P. minima from Brazil occurred in salinities below 35 o/oo and iE temperatures above 20 C, Her specimens of P. minuta from Napleswereallfromhigh-salinity water and some, atlFast, occurred in waters of 14-15 C. Vannucci was aware that different forms might be induced under different environmental conditions, but she believed the two were distinct. At this time no publication comparing the two in detail has appeared, and the question of possible synonymy is unresolved. During its autumn appearance in the plankton at Gloucester Point, salinities were about 23 o/oo, and temperatures ranged from 21 C to 18 C. The hydroid was not found in this study and is unknown to science,

Seasonal Occurrence : Medusa--September, October,

Known Range: ~edusa--Chesapeake Bay to Florida.

Family Rathkeidae

Rathkea octopunctata (M. Sars, 1835)

Rathkea octopunctata Littlef ord, 1939, p. 1070.

34 Collection Record: --York River--Gloucester Point plankton sampling station. Description: Hydroid not seen, Medusa bell-shaped, 3 mm high, mesoglea of moderate thickness, thickest at the apex, radial canals 4, velum present. Manubrium fairly large, borne on a short gastric peduncle but remaining within the subumbrellar cavity. Oral tentacles 4, given off terminally, each bifurcating distally and ending in a knob of nematocysts, intermediate pair of knobs also present about halfway along the tentacles. Tentacle bulbs 8, perradial bulbs each bearing 3- 5 f iliform tentacles, interradial bulbs smaller, bearing 2-3 filiform tentacles each. Medusa buds arising from the manubrium,

Remarks: Re octopunctata was the most abundant hydromedusa in the early w inrer Gloucester Point during 1966 and 1967, The hydroid, first described by Rees and Russell (1937), was never collected, Littleford (1939) observed this medusa in the Patuxent River during December 1938 and noted a sudden decrease in its abundance late in the month. He found evidence indicating the decrease was due to predation by Cyanea.

Seasonal Occurrence: Medusa--November, December.

Known Range: Medusa--Arctic Ocean to Chesapeake Bay and Bermuda.

Family Bougainvilliidae

Bougainvillia carolinens is (McCrady, 185 7)

Bougainvillia carolinensis Cowles, 1930, p. 331; Kramp, 1961,

Collection Record: Chesapeake Bay- -Kiptopeke.

Description: Hydroid not seen. Medusa thimble-shaped, up to 5 rnm high and wide, mesoglea very thick, radial canals 4, velum present. Gastric peduncle absent, manubrium short, with a small base, mouth simple, 4 oral tentacles branched dichotomously up to 4 times, terminating in nematocyst batteries, base long. Tentacle bulbs 4, fairly large, each bearingabout 6-9 ocelliandfiliform tentacles. Gonads on the manubrium.

Remarks : The hydroid of B. carolinensis was not collected and has not otherwise been repor bay. The medusa was identified from plankton samples in a VIMS meter net collection taken 10 October 1961. Cowles (1930) also reported the medusa from the bay" offshore waters. Known Range: Hyd.r.o.id--Maritime Provinces to South Carolina and Louisiana. -New England to Florida,

Bougainvillia rugosa Clarke, 1882 E

Bougainvillea rugosa Clarke, 1882, pa 140, figs , 21- 24,

Bougainvillia rugosa Mayer, 1910a, p. 171, plate 17; Cowles, 1930, 1944, p, 53, fig. 22; 1946, p. 41, 120; Kramp, 1959, p, 110, fig. 96; 1961, p. 82; Calder and Brehmer, 1967, pe 153.

Collection Records: York River--Ellen Island, Gloucester Point. --r--Hampton Bar, Norfolk Navy Base Pier 12, Middle Ground .

Substrates : Rope, wood (pilings, fouling rack), test panels (acrylic plastic, asbestos fiber ), Lissodendoryx -iso- dictyalis, Alcyonidium verrilli, H ona

Description: Colonyreaching 25 cm high, mostconsiderablysmaller, stems arising from a stolon mat adhering to the substrate. Stems and main branches polysiphonic, growth monopodial with terminal hydranths, branching numerous, irregular. Hydranths relatively longand tubular when fully extended, hypostome conical, tentacles 8-16, f iliform, in a single whorl. Hydranths present on main stem and branches. Per isarc wrinkled at hydranth base, occasionally elsewhere, distinct annulations absent.

Nematocysts: desmoneme~~...... ,~~~~~~~~~@4-5x 2.5-3 p (undischarged) microbasic euryteles,.,,..6,5-7.5 x 3-4 p. (undischarged)

Medusa buds borne on the hydranth pedicels only, pyriform at liberation, with 4 narrow radial canals, nematocysts scattered over the exumbrella, velum well developed. Manubrium short, bearing gonads even in newly liberated medusae, oral tentacles 4, unbranched, with nematocysts at the tips. Tentacle bulbs 4, round, relatively small, all newly liberated medusae with 12 marginal tentacles, 3 per bulb, and usually 8 red ocelli, but numbers vary slightly, additional ocelli frequently small. Ocelli in definite position, oneatthe base of each of the first 2 tentacles in each bulb, arranged clockwise about the oral end of the medusa. Umbil- icus present in most 12 hour medusae, absent in most 24 hour specimens. With increasing age and size, no change in number of marginal or oral tentacles, no branching of oral tentacles, and a slight increase in number of ocelli (Table 2), Maximum of 12 0

C\I rl

0 h] ri

C\I ri

N ri

0 h] ri

0 e h] ri

0 h] ri

0 a '3 ri

0 h] rl m a, ri U rd C,r: a, C, ri 5 G *rl b-l h ocelli per individual observed, Eleven marginal tentacles observed in occasional specimens attributable in all cases to loss through injury. Infrequently, 13 tentacles observed in older medusae, Medusae reaching a maximum of about 2.2 mm high, 2,O mm wide.

Remarks : Hydroid colonies used in laboratory culture were collected from pier pilings at Gloucester Point, Virginia. Medusae, obtained by isolating hydroids with medusa buds in f ingerbowls containing filtered seawater, were placed in Erlenmeyer flasks containing 1000 ml of water secured to a Burrell wrist-action shaker. Specimens were cultured in a constant-temperature room at 20 C and in filtered seawater of 21,5 o/oo, Medusae were fed Artemia nauplii once daily, and the water was changed every 48 Descriptions were made from living and freshly preserved

The genus is represented by several species alonq the easter es coast, but in southwestern Chesa- peake Bay, only B. rugosa is common.. Clarke's (1882) original description of tKe d was adequate, but his account of the medusa was sketchy, The description of an atypica.1 Be rugosa medusa from Charleston Harbor by Mayer (1910a), and his aFsu?i7f?EFL that it was a juvenile, led to confusion over the organism, with Kramp (1959) regarding it as a doubtful species. Mayer's medusa bore the typical 12 marginal tentacles and four unbranched oral tentacles, but 12 ocelli were also present. Since B. rugosa medusae are sexually mature at liberation, in Chesapeake Zy FfZFE mens at least, it is unlikely that his specimen was a juvenile, particularly since it was 1.5 mm in height. Medusae are evidently rather short-lived, since none were kept alive inthe laboratory longer than 20days during this study. The largest medusa collected in plankton samples measured 1.3 mm high and 1.25 mm wide, corresponding roughly to six-day-old laboratory-raised specimens, assuming equal conditions of nutrition, The largest laboratory-raised medusa was a 10-day-old specimen 2,2 mm highand 2.0 mm wide. Eighteen medusae fromplankton samples had a mean diameter and height of Oe77 mm and 0,80 mm, respectively. The egg of Be rugosa is extraordinary in beingdotted periph- erally by rather ly distributed nematocysts (microbasic euryteles), The phenomenon of an armed egg is a recent discovery, having been described by Szollosi (1969) in the egg of --Be multitentaculata from Friday Harbor, Washington. ed with ot hydroids from the North lantic, B. size and general morphol- ogy is most s imilar-to ollnensls, the species from which it may have been derived (Tra differs from B. in having per e hydranth base, only on the hydranth pedicels, and in lacking distinct annulations. The medusa of B. rugosa is distinct from any other species of the genus in haviEg UsTa31Py but 8 or 9 ocelli and 12 marginal tentacles throughout life. Other than B. rugosa, only two described species of Be have unbranched and (1961) as doubtful species. Seasonal Occurrence : --early April through early December. Medusa--May through November.

Known Range: Hydroid--Chesapeake Bay to the Caribbean Sea. Medusa--Chesapeake Bay to South Carolina.

Garveia cerulea ( Clarke, 1882 ) Plate 2, E Calyptospadix cerulea Clarke, 1882, p. 136, figs . 1-9; Cowles, 1930, p. 330; maser, 1944, p. 54, fig. 24; 1946, p. 39, 113; Calder and Brehmer, 1967, p. 153.

Collection Record: --James -River--Norfolk Navy Base Pier 12. Substrates: Rope, asbestos fiber test panels.

Description: Colony 3 cm high, stem monosiphonic, occasionally somewhat geniculate. Branching usually regular, perisarc thick, annulated at the base of the stem, branches and pedicels, terminating on the hydranth below the tentacles. Hydranth protected by a pseudohydrotheca when retracted. Tentacles filiform, 6-12 in number, arranged in one whorl. Growth monopodial with terminal hydranths. Sexes separate. Male gonophores elongate- oval, covered by perisarc, sperm developing about a distinct spadix, which may be obscured by sperm when mature. Female gonophores oval, covered with perisarc, spadix large, several planulae developing in each gonophore. Gonophores borne on the hydranth pedicels.

Remarks: G. ceruleawas first described from Fort Wcol in Ham~ton Roads by -clarke (1882) as Calyptospadix cerulea. It i s proposed here that the monotypic genus Clarke, 1882 be placed in synonymy with Garveia Wright, 1859, there being no feature in Clarke's description, or in specimens observed in this study, to warrant distinction of the two. Clarke's original description of was as follows:

"Trophosome. Hydrophyton consisting of a branching hydrocaulus rooted by a creeping, filiform hydrorhiza. Hydranths fusiform with filiform tentacles which are arranged in a single verticil round the base of a conical hypostome. Perisarc developed into large hydrotheca-like processes. Gonosome. Sporosacs developed on the ultimate ramuli beneath the terminal hydranths,??

--Garveia was defined by Allman (1872) as follows: "Trophosome. Hydrophyton invested with a conspicuous perisarc, and consisting of a branching hydrocaulus, rooted by a f iliform hydrorhiza, Hydranths f us iform, with f iliform tentacles, which are disposed in a single verticil round the base of a conical hypostome. Gonosome. Sporosacs developed from the hydrophyton, where they are borne on the summit of a short ramulus."

The pseudohydrotheca, considered diagnostic by Clarke (1882) and Fraser (1944) for Calyptospadix, covers the hydranth only when it is contracted. ructure is seen in Garveia and

is very similar to Bimeria, the two being esence or absence of perisarc covering the e tentacles, Torrey (1902) considered this criterion to be insufficient basis for generic distinction, and placed in synonymy with The two genera have subs eq een united by some atists and kept separate by others. Both genera are recognized here, but re-examination and possible revision of these hydroids is desirable, as Rees (1938) noted. G. and G. areverysimilarmorphologically and wer e stinFui the end of the survey. Conse- quently, the collection records reported here forthe two species, based solely on re-examined specimens, are inadequate indication of the abundance and widespread occurrence of Garveia hydroids in the study area. During summer and autumn, Garveia was very abundant in meso- and oligohaline waters of the James, York, and Rappahannock rivers, but which species was represented, orwhether both were present, is unknown. However, Cory's (1967) data from the Patuxent River, together with the present record of G. franciscana from low salinities, and Vervoort 's (1964) distribution st that the abundant of low salinities is Morphologically, G, is distinct in having lae, rather than one, ping in each female gonophore. The blue color of the female gonophores, eggs, and young planulae, thought to be unique to this species (Hargitt, 1909), was also observed in -G. franciscana. Known Range: Hydroid--New Brunswick to Chesapeake Bay.

Garveia franciscana (Torrey, 1902)

Bimeria tunicata Fraser, 1946, p, 42; Frey, 1946, p. 86. -- --_I-- --Bimeria franciscana Cory, 1967, p. 79, Collection Record : --James River--Deep Water Shoal, Substrates: Wood pilings, ---Crassostrea virginica- shells. Description: Stem straight, monos iphonic, reaching 7 cm high, branching more or less regular and alternate, perisarc thick, horn colored, annulated at the base of branches and pedicels, of ten wrinkled on pedicels, but smooth elsewhere Hydranths partially covered by a pseudohydrotheca, manubrium dome-shaped, tentacles about 8-10, f iliform, in a single whorl. Sexes separate with gonophores borne on the hydranth pedicels . Male gonophores elongate-ovaland coveredwithperisarc, spermatozoa developing around a distinct spadix, Female gonophores round or oval, covered by perisarc, spadix large, one planula produced in each gonophore ,

Remarks: Originally described by Torrey (1902) from San Francisco Bay, California, G. franciscana was first recorded on this coast in Louisiana by FrZse Shortly there- after it was found i (1946), Deevey (1950) compared hydroids from Louisiana and Texas with specimens from San Francisco Bay and synonymized B. tunicata with B. franciscana, Vervoort (1964) demonstrated Fy microscopical sections perisarc does not cover the base of the tentacles in ies and removed it to the genus In Chesapeake Bay, Cory (1967) fo s species to be abundant on test panels in the mid-estuary of the Patuxent River, Maryland.

Known Range: --Hydroid--Chesapeake Bay to the Gulf of Mexico,

Aselomaris michaeli Berrill, 1948 T --- --Aselomaris - michaeli Calder and Brehmer, 1967, p. 153. Collection Records : York River--Gloucester Point, ----Norfolk Navy Base Pier 12. Substrates: Asbestos fiber test panel, pontoon float, stern of skiff, fiberglass wet table lining, plastic trays, Zostera marina,

Description: Zooids arising singly from a stolon network, but forming dense colonies, Stem varying in lengthwithage, reaching 1,5 cm, Hydranth fusif orm with a cone-shaped man.ubrium, tentacles about 20, f iliform, in 2 or 3 close verticils, appearing almost scattered in extended hydranths Perisarc thin, smooth, terminating below the hydranths, Gonophores fixed, arising from the stems only. Gonophore pedicels short when young, increasing in length with age. Female sporosacs round to oval in shape, with a prominent spadix. Male sporosacs elongate-oval, spadix distinct, Remarks : Berrill (1948) redefined the genus As elomaris to include bougainvilliid hydroidswithhydranths aris om creeping stolons, and with gonophores reduced to s ising only fromthehydranth stalk. The definition ofthegenus was broadened to include A. michaeli, a species found by Berrill throughout the ~oothbay-H ion of Maine. It is distinguishable from its closest re arenosa, in lacking a pseudohydrotheca and gelatinous perisarF. believed A. was either an extremely local specie d been over sewhere and suggested it was a northern species extending to but not south of Cape Cod. The first report of A. outside its general type locality was for Hampton Rza r and Brehmer, 1967), It was a fairly common hydroid t the winters of 1966 and 1967 at Gloucester Point, particularly just below the water line of objects floating at the surface. A. identified in the collection of Re Morales-Ala it from water-warming jugs of VIMS Malacology Department on 15 January 196 2.

Seasonal Occurrence: Hydroid--mid-October through early June, res--mid-November through early June.

Known Range: Hydroid--Maine to Chesapeake Bay.

Nemopsis bachei L. Agassiz, 1849

Nemopsis bachei Mayer, 1910a, p. 173, plate 17; Cowles, 1930, Pe 3 mp, 1961, p. 89. Collection Records : Rappahannock River--Urbanna, sh Light to P-30, - -Hampton Roads. Bay--Station C-00 to York River entrance.

Description : Hydroid not seen, Medusa thimble-shaped, up to 1,5 cm high and wide, mesoglea thick, radial canals 4, velum present. Gastric peduncle absent, manubrium short, quadrate, oral tentacles 4, branched dichotomously up to 8 times, base very short and thick. Tentacle bulbs 4, large, V-shaped, each beari~g up to about 26 ocelli and tentacles, 2 of which are short and capitate. Gonads ribbon-like and slightly folded, extending from the manubrium out along the radial canals nearly to the tentacle bulbs . Remarks: This was the most conspicuous hydromedusa in southern Chesapeake Bay because of its relatively large adult size and periodic abundance. During 1966 and 1967, it was collected at Gloueester Point eight months of the year, being absent only during February-March and September-October, Collection records indicate N. bachei is extremely eury- haline. Simmons (1957) reported l"t ndance at 45 o/oo in the Laguna Madre, Texas, and along the Mississippi coast Moore (1962) found it in salinities as low as 5.64 o/ooe According to Moore, it apparently does not occur around southern Florida, but he was uncertain whether it is a disjunct species or if it had been introduced recently to the Gulf Coast. Despite the abundance of the medusa, its hydroid was not collected in Chesapeake Bay. Mayer (1910a) included a description of the hydroid based on observations by Brooks, who found it growing on a submerged piece of wood in Newport River, North Carolina. Fraser (1944) did not include it in his monograph, Very young medusae of N. bachei were obtainedat Gloucester Point, indicating the probabfe presence of the hydroid in the area.

Seasonal Occurrence: Medusa--April through August, November through January.

Known Range: Hydroid--North Carolina. -Nova Scotia to Florida and the northern Gulf of Mexico ,

Family Pandeidae

Amphinema dinema (~6ronand Lesueur, 1809 ) e 7, G

Collection Records : Chesapeake Bay--Cape Charles, Fisherman's Island,

Substrate : Alcyonidium verrilli.

Description: Hydroids small, reaching 4 nun high, zooids arising singly from a stolon network, stems very thin. Hydranths clavate when extended, with a dome- or cone-shaped manubrium, Perisarc very thin, smooth, terminating at the hydranth base. Tentacles about 8-10, all filiform, in two close whorls, Gonophores oval, arising from the stolon via a moderately long pedicel, freemedusaeproduced, One-day-old medusae thimble- shaped, 0-7 mm high, 0.6 mm wide, mesoglea thin, apical process absent, velum well developed, 4 radial canals. Manubrium short, cone-shaped, lips absent. Tentacle bulbs 4, two opposite ones small, lacking tentacles, and two large ones with long filiform tentacles. Adult medusae (3 days old ) with cruciform manubrium, lips present, gonads, marginal warts and an apical projection present. Older medusae (25 days old) umbrella-shaped, le5mm wide, 2.0 mm high, with a long cone-shaped apical projection, Radial canals 4, velum and mesoglea fairly thin, Tentacles 2 or 3, perradial, filiform, very extensible, arising from very large tentacle bulbs, ocelli absent. Manubrium cruciform, bearing 4 pairs of gonads, each pair on either side of the perradial axis, gonads suspended dorsally from the radial canals, mouth with 4 lips, Marginal warts present.

Remarks: Very little is known about this hydrozoan in Chesapeake Bay, all records having been made from the eastern shore during summer 1967. The hydroid was first collected on 10 August 1967 at Cape Charles in 2 m of water, Medusa buds were present, and medusae were released from the hydroid after about 48 hours in the laboratory, Medusae were reared in petri dishes containing 21.5 o/oo seawater in a constant temperature room at 20 C. The water was changed daily and Artemia nauplii were used as food, After development of gonads, it was possible to identify the medusae as Amphinema dinema, Two of the three medusae cultured longer th three marginal tentacles ; the third tentacle, process, was nearly as well developed as the original two within two to three weeks, All specimens were preserved after 25 days, The medusa was linked to the hydroid Peri- dies by Rees and Russell ( Perigonimus is no longer species iB a Bougainvillia and must be placed ra, apicatus, des ok s na, was referable to A, dinema, the hydroid of which has not otherwise been reported-fr s coast. Rees' assumption is not accepted here because medusa buds were given off from the stems in -P. apicatus and not from the stolons as in -A. dinema, Known Range: Hydroid--Chesapeake Bay. -Massachusetts to Florida, L

Family Proboscidactylidae

Proboscidactyla ornata (McCrady, 1857)

Proboscidactyla ornata Calder, 1970b, p, 130, fig. 1,

Collection Records: York River--Gloucester Point, --s==r--Nansemond Ridge, Hampton Flats, Substrate: Sabella microphthalma tubes.

Description: Hydroid colony consisting of 2 tentacled gastrozooids andtentacleless yonozooids, color creamtogoldenororange. Gastrozooids in a s irigle row at the orif ice of the sabellid tube, usually forii~ingacompletering about the margin. Tentacles filiform, arising from a cormon area 3/4 of the distance apically. Gastrozooids reaching 1.3 mrn high, 0-2 mm wide, girth maximal in the mid-region* Tentacles extensible, to 1.5 mm. Manubrium separated by a constricted region and curved to face the center of the worm tube lumen, Gonozooids smaller, 1 mm high, 0-1 mm wide, terminating in a mouthless knob, Gonozooids usually origi- nating near the proximal end of the gastrozooid, or several mm down the worm tube, remaining in contact via a stolon, Medusa buds developing 1/2 to 2/3 of the distance apically, 4 buds developing concurrently per gonozooid, 5 noted in one case. Just before liberation, medusa with 4 unbranched radial canals, 4 perradial tenta.cles and tentacle bulbs, and 4 interradial cnidothylacies . Velum well developed, ring canal and gonads absent . Manubrium simple, short ; tentacle bulbs and manubrium golden or orange. At liberation, medusae 0,6 mm high and wide, mesoglea thin, umbilicus present, disappearing within 24 hours. Adult medusa hemispherical, about 2 mm high and wide, mesoglea quite thick, Primary radial canals 4, branched 1-2 times, tentacle bulbs 8-16, tentacles f iliform, one per tentacle bulb, ocelli absent. Velum distinct, gonads ~erradial,on the manubrium, manubrium short, quadrate, mouth frequently with outward expanded lips.

Remarks: Proboscidactyla hydroids have been found exclusively in this study only on bearing worm tubes were rom the VIMS west pier at a depth of 2.5 m. They were also common at depths of 2-4 m on pilings of the same pier, among sponges, hydroids, bryozoans, and ascidians, Colonies from the James River were obtained on sabellids attached to shells of and nar ia in 3 m of water, rela common mer at Gloucest

Seasonal Occurrence : Hydroid--early April through early January. -June through September, Known Range: Hydroid--Chesapeake Bay. -Massachusetts to the Caribbean Sea,

Family Eudendriidae

Eudendrium album Nutting, 1898

Collection Records: York River--Gloucester Point, Page ts Rock, ----Hampton Flats, Middle Ground, Newport News Bar. Description: Hydroid colony small, reaching 1.5 cm in height, stems rnonosiphonic, branches few or absent, perisarc moderately thin, smooth or slightly wrinkled with indistinct annulations present at the base of stems and branches, perisarc terminating just below the hydranths, Hydranths with a trumpet-shaped manubrium and a single whorl of about 18-20 filiform tentacles. Gonophores fixed, borne near the base of non-aborted hydranths . Remarks: The commonest Eudendrium encountered during the survey was E. album, not repo in Chesapeake Bays It was partycu common in Hampton Roads during summer. Although inconspicuous due to its small size, careful examination of such substrates as oyster shells and Sertulariaargentea stems frequently resulted in its collection,

Seasonal Occurrence: Hydroid--early May through mid-November. es--mid-June through late September,

Known Range: Hydroid--Maritime Provinces to Florida.

-Eudendrium carneum Clarke, 1882 Eudendrium carneum Clarke, 1882, p. 137, figs. 10-17; Cowles, Fraser, 1944, p, 64, fig, 36,

Remarks: E. carneum was described by Clarke (1882) from Hampton Roads, where orted "immense quantities" on piles at Fort Wool during summer. There is no other record of the hydroid in Chesapeake Bay, although Cowles (1930) and Fraser (1944) noted it was known from Fort Wool, in reference to Clarke" paper. While colonies were seen during this survey at Beaufort, North Carolina, it was never encountered in Chesapeake Bay. The hydroid is large and conspicuous because of its bright red hydranths and is not easily overlooked. Evidently the species has been elimi- nated from the bay by some factor or combination of factors.

Known Range: ~~droid--MaritimeProvinces to the Caribbean Sea.

Eudendrium ramosum (Linnaeus, 1758)

Collection Records : York River--of f VEPCO at Yorktown. r--Midd le Ground. PP Substrates: Leptogorgia virgulata, Anadara transversa and Crassostrea vlrglnlc s. Description: Stem and main branches polysiphonic, colony large and bushy, reaching 15 cm high, branching irregular, perisarc thick, horn colored in older regions, distinct annulations present at the base of branches and pedicels, smooth elsewhere. Hydranth with a trumpet-shaped proboscis, tentacles about 20-25, f iliform, in a single whorl. Gonophores not seen,

Remarks 2 This hydroid was identified from spechens lacking gonosomes, and the identification must beregarded with some reservation because Eudendrium is a large genus containing many species readily dist only when the gonosome is present. The largest colony observed was 15 cm high, collected in the dormant state 9 January 1967 at Middle Ground, Hampton Roads. After six days at 19-20 C in a constant-temperature room, extensive growth and abundant hydranths were noted. The only feature readily distinguishing the colony from E, carneum was the color of the hydranths, which, in commonwith?7ther specimens of the type collected during this study, were not bright red but whitish to greenish with pink endoderm,

Known Range: Hydroid--Labrador to the Caribbean Sea.

Order Leptomedusae (Thecata) Family Haleciidae

Halecium gracile Verrill, 1874

Collection Record : Chesapeake Bay--Station C-00.

Description: Hydroid represented by small fragments only. Stem straight, divided into relatively long internodes by transverse septa, annulations absent, Hydrophores pedicellate, pedicels arising from a shoulder-like process at the distal end of the internode. Hydrothecae with a distinct diaphragm just below a row of punctae, margin flaring but little, hydranth with about 22 tentacles. Hydrophores often renovated, secondary hydrophores borne on pedicels frequently as long as the primary hydrophore. Gonophores not seen.

Remarks: Four unattached fragments of this hydroid were found in a bottom plankton sample taken 13 December 1967 by V. G. Burrell, Jr. Fraser (1946) regarded H. gracile as a tropical species, despite its extended range intz t west Atlantic, where it occurs as far north as the Gulf of St. Lawrence,

Known Range: --Hydroid--Gulf of St. Lawrence to the Gulf of Mexico. Family Campanulariidae

The family Campanulariidae is in need of comprehensive revision, Among hydroid systematists, the number of genera included in the family ranges from two by Broch (1918) and others who recognized only Campanularia and Laomedea, to Stechow (1923) and others who adm 17 genera, Among Students of the medusae, Kramp recognized five genera--Agastra, Eucopella, To date, no maj id hydroids and the medusae

For this work, hydroids liberat medusae are retained and hydroids liberating medusae are placed for priority reasons, nulariid genera of medusae ormedusa-producing hydroids were not found, and no further union of hydroidandmedusa under thesamegenus is advanced here, However, two species of hydroids in this family which do not liberate medusae were found. These were Hartlaubella gelatinosa ; their synonymies has been drop municat ion), who pointed out that it is a synonym of Obelia, In summary, the campanulariid hydrozoans of ~hesa~ehkeBa in the genera Clytia, -Obelia, Gonothyraea, and Hartlaubella ,

Clytia cylindrica L. Agassiz, 1862

Collection Records : --York River--Tue Marsh Light, Perr in, VEPCO (Yorktown) outfall, Gloucester Point. --James River--Hampton Flats. Substrates : Zostera marina, Garveia sp., Sertularia argentea, Hydroide es ostrea virqinica

Description : Creeping stolon giving rise to pedicels reaching 4 mm high with usually 8-10 annulations proximally and 3-4 distally. Pedicel 53- 86 p wide, occasionally branched, branch annulated proximally and distally, bending abruptly upward at the origin and forming an acute angle with the pedicel, Hydrothecae 300- 435 1 long, 172-248 p wide, margin with about 7-10 sharp, deeply cut triangular teeth, diaphragm distinct. Gonothecae not observed.

Remarks: Working alongthe entire New Zealand coast, Ralph (1957) found considerablevariabilityinClytia johnstoni(=C. hemisphaerica) and suggested C. species. However, Ve separate species, as h species from Chesapeake Bay differ in the following respects : Clytia cylindrica Clytia hemisphaerica Hydrotheca length width Number of teeth

Known. Rang.e. : Hydroid--New Brunswick to the Caribbean Sea.

Clytia edwardsi (Nutting, 1901)

Clytia edwardsi Calder and Brehmer, 1967, p. 153.

Collection Records: York River--Gloucester Point, Bell Rock. --Middle Ground, Norfolk Navy Base Pier 12. Bay--Willoughby Bank, Thimble Shoal, Chesapeake Bay Bridge-Tunnel (Virginia Beach span).

Substrates: Wood piling, rubber tire, test panels (acrylic plastic, asbestos fiber), Zostera marina, Microciona prolif era,

lmprovlsus s Description: Creeping stolon giving rise to pedicels up to 2 cm high, 79-119 JI. wide, annulated proximally and distally. Pedicels occasionally unbranched but typically branches present, tangled with upright stolons to form a dense colony. Branches bending upward abruptly at the origin forming an acute angle with the pedicels. Hydrothecae 750-1050 JI. long, 427-488 p wide, margin with 10-12 triangular blunt teeth, diaphragm distinct, basal chamber rather deep. Gonothecae corrugated, growing from the hydrothecal pedicels and supported on pedicels with 2 to 10 or more annulations. Gono- thecae variable in shape, elongate or bluntly clavate, reaching a maximum diameter distally, 232-364 ,u wide, 728-1523 p long, apex truncate.

Remarks: This is the largest species of the genus in southern Chesapeake Bay. It is evidently quite eurythermal and sporadically abundant but most common in winter and spring, Little is known about its reproductive seasonality since gonangia were observed only during April, both in 1966 and 1967, Asexual reproduction by stolonization appears to be relatively common.

Seasonal Occurrence: Hydroid--early October through early July. Known Range: --Hydroid--New Brunswick to Chesapeake Bay.

Clytia hemisphaerica (Linnaeus, 1767) mate37

Collection Records : Pamunkey Ri~er--P-35~ iddle Ground, Deep Water Shoal, Hog Island, -- P Substrates: Garveia sp., Sertularia- ---argentea, Description: Creeping stolons giving off pedicel~up to 5 mm high, usually much shorter, when present, branches fewand irregular, bendingupward abruptly at the origin. Pedicels and branches annulated proximally and distally, pedicel 53-86 p. wide, Hydro-

thecae 40 5- 615 p long, 240-338 p wide9 margin with ' about 12 sharp, triangularandrather deeply cut teeth. Diaphragm well developed and distinct. Gonothecae not seen.

Remarks: Clytia johnstoni has long been known to be the hydroid tonlyrecently (Millard, een put forward for the Millard in the proposed name change. Curiously, the medusa, very common in Europe, has never been reported onthis coast, while the hydroid, reported as C. johnstoni by Fraser (1944) and others, is well known, This aiscrepancy suggests that the North American hydroid reported as C. johnstoni may actually belong to another species, and a clari- TyiiFiTfammic study is needed, In this study the hydroid was observed in abundance only in oligohaline waters.

Known Range: Hydroid--Arctic Ocean to the Caribbean Sea.

Clytia kincaidi (Nutting, 1899 ) 33----

Collection Records: York River--Gloucester Point. ----Hampton Flats, Substrates: -----Sertularia argentea, --Crassostrea virginica shells, Description: Pedicel reaching 3 mm high, arising from a creeping stolon, unbranched, annulated proximally, distally, and occasionally medially, 33-47 p wide. Hydrothecal margin bearing pleats and about 7 deeply cut teeth, hydrothecae 450-540 long, 172-218 wide, diaphragm thin, Gonothecae not observed. Remarks: This hydroid was observed only twice, and in both collections very few specimens were present. The species is very small, the pedicel resembling that of C. paulensis, The pleated margingavethe hydrotheca a superficiaxre e to operculate forms with the operculum partly open. It was collected only in September 1966 and July 1967 and gonosomes were never observed. Nutting (1899) originally describedthis species from Alaska and Puget Sound. The only other record of the species for this coast is from the Lesser Antilles (Leloup, 1935).

Known Range: --Hydroid--Chesapeake Bay to the Caribbean Sea,

Clytia paulens-- is (Vanhijf f en, 1910 ) FIaF3

Collection Records : --York River--Tue Marsh Light, Ellen Island, off VEPCO at Yorktown, Gloucester Point, Page ?s Rock. ----James -River--Old Point Comfort, Hampton ~lats,Newport News Bar, Middle Ground. Chesapeake --~a~--~hesapeake Bay Bridge-Tunnel (mid-span).

Substrates: Halichondria bowerbanki, Ectopleura dumortieri,

ercenarla nsversa, TFZSs-ea virginica .------Description: Colony consisting of a creeping stolon and upright pedicels which mayormay not be branched, When present, branches arising abruptly at the origin and nearly parallel the pedicel. Pedicel strongly annulated proximally, distally, and sometimes medially. Hydrothecae cylindrical, tapering abruptlyatthe proximal end. Margin with about 6-7 deeply cut bicuspidate teeth. Gonangia arising from the stolon or from the hydrothecal pedicel, gonothecae clavate, apex truncate.

Remarks: Hydroids from Chesapeake Baywere compared with specimens of C. paulensis from South Africa provided by Dr, N. A. H. Millard ( TaFleT two populations are very similar morphologically, and there can be little doubt that they are conspecific. The hydrothecae of Chesapeake Bay specimens tended to have about one less marginal tooth, but even in this apparent difference there was overlap between the two populations. Millard (1966) noted that the sizeand proportions of the hydrotheca are very variable from region to region. This species has not been previously reported from this hemisphere, being known from South Africa, Australia, and Antarc- tica. However, there is nothing in Fraser's (1914) description of Clytia longi to distinguish it from C, and the two-SpmeTEiaY nonymous . Verification o st await a critical examination of ~raser'sspecimens. -C. longitheca is Table 3. Comparison between Clytia paulensis from the York River, Virginia, a of South Africa. Measurements are in microns.

Virginia South Africa South Africa (Millard, 1966)

Pedicel length 560-1760 450-2200 diameter 30-45 3 5- 60

Hydrotheca length 410-600 490-640 diameter 140- 180 150- 210

Gonotheca length 670-950 diameter 170-300 known from British Columbia to San F'rancisco Bay (Fraser, 1937a). C. ulvae Stechow, 1919 from Marseilles may also be synonymous with T.- -ensis (Millard, 1966). Seasonal Occurrence: Hydroid- -mid- May through early December.

Obelia Clark, 1876 Plate 3, J

Obelia bicuspidata Calder and Brehmer, 1967, p. 153.

Collection Records: --York River--VEPCO (Yorktown) outfall. --James River--Hampton Ban, Norfolk Navy Base Pier 12, Substrates: Asbestos fiber test panels, Garveia sp.

Description: Colony about 1 cm high, hydr ocaulus monosiphonic, branching irregular. YBin stem straight or slightly geniculate, distance between the origin of two hydrothecal pedicels short, 298-430 u. Stem with 4-6 annulations above each pedicel. Hydro- thecae borne on short pedicels annulated throughout. Hydrothecal margin with about 10 bicuspidate teeth, cusps occasionally as deeply cut as the teeth, Diaphragm thin. Gonothecae oblong- ovate, 596- 728 y long, 216- 22 5 ,u wide, arisinginthe axilofthehydrothecal pedicels. Gonothecae truncate distally or narrowing abruptly, forming a rather poorly developed collar.

Remarks: Bicuspidate campanularian hydroids are among the most widelydistributedand abundantthecates insouthern Chesapeake Bay, yet the possibility of two species being represented was not dis- covered until after field collections were terminated. The two species Obelia bicuspidataand0.longicyathaare- not separable from the ecological data recorded, and the only information presented here is that from specimens preserved in the hydroid collection. Distinguishing features between Chesapeake Bay specimens of the two species include:

Obelia bicuspidata Obelia longcyatha Hydrotheca length 360-385 ,LI 480-563 p width 188-210 JI 188-225 ,LI Colony size small (about 1 cm) large (up to 25 cm)

Such apparent differences may represent only a gradation in form, and it is possible that the two are actually conspecific. Both are retained here on the basis of insufficient data and the absence of a thorough comparative study of the two. Deevey (1950) noted that 0. bicuspidata is amorphologically variable species probably mes. Vervoort (1968), who encountered 0. from Caribbean collections, expresyed of both. He reported the general ilar in both, although those of -0. nd relatively more slender. collection made during this study, were those e on 14 July 1965, and from the VEPCO Yorktown outfall on 26 September 1967 where the water temperature was 27 C (7 C above ambient water temperature in the York River). Specimens collected 29 July 1958 from Hampton Bar and identif Ted by Dr. W. G. Hewatt as Clytia were re-examined and found to be 0. onophores of this hydroid werenotzes 1 1910 by Fraser, who found them tobe very small, ovate or oval in shape, with the top truncated or inverted at the apex. In this study, gonothecae were of moderate size and similar to those observed by Vervoort (1968).

Known Range: Hydroid--Maine to the Caribbean Sea,

Obelia commissuralis McCrady, 1857

Obelia commissuralis Calder and Brehmer, 1967, pa 153. P Collection Records : York River--Gloucester Point. --Norf o& Navy Base Pier 12, Bay--Chesapeake Bay Bridge-Tunnel (mid-span); v mid-bay (37" 15?N, 76" 10 'W) . Substrates : Steel barrel, asbestos fiber test panels, Myt ilus edulis, Crassostrea virginica shells, Balanus eburneus s Description: Colony reaching 5 cm high, stem flexuous, monosiphonic, horn colored in older portions. ~rakhingnumerous, regular, bifurcating near the base such that branches extend outward as if given off from all sides of the stem, branches geniculate. Hydrothecae campanulate, marginentire, diaphragmthin, hydrothecae 285-428 JI long, 185-285 p wides Gonothecae club-shaped, arising in the axils, truncate distally with a distinct collar, length 463-728 p, width 265-298 pe

Remarks: In collections from the river estuaries of the western bay, this species was rare, being abundant only in the middle and lower bay. Little is known about its seasonality, although it appears to be a summer form. The best specimens observed were collected 15 June 1966 from 37" 15 P~,76" 10 WW, At this station, water temperature was 21 C and salinity was 17 -11 o/oo. Known Range: Hydroid--Maritime Provinces to South Carolina, possibly to Tortugas, Florida.

Obelia dichotoma (Linnaeus, 1758)

Collection Records: York River--Tue Marsh Light, Glouces ter Point, --Bay--New Point Comfort, Kiptopeke Beach, Substrates: Wood ~ilincrs,Zostera marina. Halichondria bowerbanki, ~ou~aihvillra' lr ostrea virginica S 2 e Description: Colonyreaching 2.5 cmhigh, hydrocaulus monosiphonic, branching irregular, more or less geniculate. Hydrothecae 375- 428 p high, 225-300 p wide, hydrochecal margin wavy, diaphragm thin. Gonothecae axillary, club-shaped, with a distinct terminal collar.

Remarks: This hydroid is common at Gloucester Pointduring summer, particularly near mean lowwater on pilings and adhering invertebrates.

Seasonal Occurrence: Hydroid--late May through late November,

Known Range: Hydroid--Quebec to the Caribbean Sea.

Obelia geniculata (Linnaeus, 1758)

Collection Records: --York River--Tue Marsh Light, Guinea Neck, Perrin, Gloucester Point. Chesapeake Bay- -New Point Comfort, Cape Charles. Substrate: Zostera marina,

Description : Hydroid colony 1,5 cm high, stem monosiphonic, geniculate, unbranched or irregularly branched. Hydrothecae campanulate, margin entire, diaphragm very thick. ~~drothecal pedicels usually short and annulated throughout. Gonothecae axillary, oval, supported on a short annulated pedicel and te~minatingin a distinct collar.

Remarks: This hydroid was found in greatest abundance on eelgrass near the York River entrance, but in the river --per se was Table 4. Comparison of Obelia geniculata hydroids from Chesapeake Ba olonies from ~assama~uodd~-Bay, New gunsw wick .

Passamaquoddy Bay Chesapeake Bay

Substrate Laminaria sp. Zostera marina

Maximum observed height 2,O cm 1.5 cm

Internode length width annulations

Annulat ions in pedicel proximally 5- 6 distally 2- 3

Hydrotheca length width

Mature gonotheca position axillary axillary length 0.83-0.86 mm 0.70-0.83 mm width 0.30-0.33 mm 0,30-0.33 mm terminal collar present present observed solely on unattached eelgrass. It was collected sporadically elsewhere, suggesting a limited abundance and restricted distribution in Chesapeake Bay. Chesapeake Bay specimens differ from descriptions of other 0. geniculata from North America in the thinness of the stem reas in typical 0, colonies the perisarc particularly on t ide of each internode, in Chesapeake Bay specimens the perisarc is uniformly thin throughout. A comparison of Chesapeake Bay colonies with typical 0, om Deer Island, New Brunswick, Canada, Ts is a morphologically variable species, as In New Zealand she found that colonies from the subantarctic were eight times taller than colonies from the subtropics, A poleward increase in branching and in the size of the internodes and gonothecae was also noted, Ralph redefined the species to encompass her observations but did not mention variation in per isarc thickness. Although the thinness of the hydrocaulus perisarc in Chesa- peake Bay specimens is a real and constant feature, it is apparent that the bay population should be retained in the same species as the more typical 0. Other differences appear to be insignif icant, an3 t e little doubt that it is closely related and conspecific to populations having the perisarc of the hydrocaulus thick.

Seasonal Occurrence: Hydroid--early June through late October,

Known Range: Hvdroid--Arctic Ocean to the Caribbean Sea.

Obelia longicyatha Allman, 1877

Clytia longicyatha Frey, 1946, p. 86.

Collection Records : Vork River--Gloucester Point, --r--Hampton Bar Substrate: Rope,

Description: Colony large, reaching 25 cm high but most much smaller, stem polysiphonic, branching regular, from all sides of the hydrocaulus, Stem and branches straight, pedicels of varying length. Hydrothecae cylindrical, 480- 563 y long, 188- 225 wide, margin with about 10 bicuspidate teeth, diaphragm thin. Gonothecae not observed.

Remarks: The similarity between and confusion over this species and -0. bicuspidata have already been discussed. -0. longicyatha- is probably much more widely distributed than the above records indicate. Although it is impossible to determine from the recorded data, either or both 0. bicuspidata and 0. longicyatha were widespread on numerous Tubstrates in the ~zpp ork, James and Elizabeth rivers, as well as in the bay itself. Frey (1946) found 0. idely dispersed in small numbers on oyster bars iF t ver, especially in late summer and autumn,

Known Range: Hydroid--Massachusetts to the Caribbean Sea,

Obelia longissima (Pallas, 1766)

Collection Records: Chesapeake -Bay--Fisherman's Island, Chesapeake Bay Bridge- Tunnel (mid-span).

Substrate: Mytilus edulis shells,

Description: Colony large, 10.5 cmhigh, stem monosiphonic, horn- colored, branching regular, alternate, from allsides of the stem. Stem somewhat geniculate, pedicels usually short and completely annulated . Hydrothecae campanulate, 585-662 p long, 339-431 ,p. wide, margin wavy, diaphragm thin, basal chamber large, Gonothecae axillary, oval, 1086-1430 p long, 418-484 p wide, small collar present apicallys

Remarks: This species was first collected on 27 March 1968 when it was relatively common on Mytilus edulis. The largest colony seen was unattached, entang piece of rope hanging from a pound net stake. The hydroids were healthy, gonosomes were abundant, and medusae were later liberated from the hydroids in the laboratory. Surface water temperature at the collection site was 8 C, A second collection was made 20 June 1968 near the mid-span of the Chesapeake Bay Bridge-Tunnel in 8 m of water. The colony was in very poor condition, and gonosomes were absent. Surface water temperature at the station was 23 C.

Known Range: Hydroid--Arctic Ocean to Chesapeake Bay.

Obelia spp. 7, 1 Collection Record : --York River--Gloucester Point plankton sampling station. Description: Young medusae tiny, about 0.25 mm across the bell, flat, velum rudimentary, tentacles 16-24 or more, manubrium urn- shaped, with 4 simple lips. Gonads, if present, midway along the 4 radial canals, Mesoglea thin, Tentacle bulbs rather small, tentacles stiff. Marginal vesicles 8, each with one concretion. Older medusae like the juveniles but larger and with numerous tentacles.

Remarks : Modern systematists have recognized that it is impossible to satisfactorily distinguish the medusae of various Obelia hydroids, six species of which are known from Chesapeak All such medusae encountered in the plankton during this study were treated as Obelia sp.

Seasonal Occurrence: Medusa--May through October,

Gonothyraea loveni (Allman, 1859)

Gonothyraea loveni Calder and Brehmer, 1967, p. 153.

Collection Records: Rappahannock River--Hogge House Ground, ~owler'sRock, Island, Gloucester Point, Cheatham Annex, Rock, Bell Rock. --James River--Sewellas Point Spit, Sewell's Point, Norfolk Navy Base Pier 12, Hampton Flats, Middle Ground, Pig Point, Nans emond Ridge --Hospital Point, -Chesapeake Bay Bridge-Tunnel (mid-span).

Substrates : Rope, wood pilings, test panels (wood, asbestos fiber, acrylic plastic), brick casing, glass bottle, metal rod, rubber hose, rocks, Gracilaria sp,, Zostera marina, Lissodendorvx isodictval ndr ia to-

Description: Colony with monosiphonic stem, reaching 4 cm high, branching alternateand rather regular, stem only slightly geniculate, Hydrothecae deeply campanulate, margin with about 12-13 truncate teeth, 397-662 p long, 212-331 p wide. Gonothecae axillary, nearly cylindrical for much of their length, 927-1225 J.I long, 298-331 $1 wide, terminal collar absent. Ova and sperm developing within meconidia extruded from the apex of the gonothecae but remaining attached to the blastostyle,

Remarks: In recent years Gonothyraea has been placed in synonymy with Laomedea by many systematists, Since Eaomedea is synonymous with Obelia and Obelia hydroids liberate medusae, been use these hydroids have fi Retention of is in accord with advice Rees (persona ion), Gonothyraea loveni was one of the more conspicuous winter hydro ead in occurrence and present on numerous substrates. It was particularly abundant in shallow water on pilings and shells. The species is not known south of Chesapeake Bay, but its abundance in this area, coupled with its eurythermy, suggest that it may occur in lower latitudes. The hydroid has been found active inthesouthern bay at temperatures from 0 C to 24.5 C.

Seasonal Occurrence: Hydroid--early November through late June, - es--early November through early June. Known Range: Hydroid--Arctic Ocean to Chesapeake Bay,

Hartlaubella gelatinosa ( Pallas, 1766)

Collection Records: York River--Gloucester Point, Page ?s Rock, --Sewell's Point Spit, Hampton Bar, Middle -- Ground, Nansemond Ridge, Brown Shoal. Chesapeake Bay--Thimble Shoal, Willoughby Bank, Chesa- - peake Bay Bridge-Tunnel (mid-span).

Substrates : Rock, rope, wood pilings, Sertularia argentea, tubes, Crassos Is,

Description: Colony large, up to 31 cm high, stem and larger branches polys iphonic, branching regular, from all sides of the stem, branches short, geniculate, profusely rebranched forming a dense colony. Hydrothecae deeply campanulate, 364-430 p long, 212-231 y wide, margin with about 10 teeth, each with a V-shaped indentat ion, diaphragm thin. Gonothecae stout, 695-960 p long, 331-463 p wide, axillary, abruptly truncate distally with a well developed collar.

Remarks: This species has had a difficult taxonomic history, having been placedatvarious times in such genera as Sertularia, Obelia, Campanularia, s do s in gonosome to be so unli ther campanulariid that it merited placement in a separate genus, Unfortu- nately, Obelariawas used by Haeckel(1879) in reference toanother coelenterate, and a new generic name, Hartlaubella, was erected by Poche (1914), Since Laomedea is synonymous with Obelia and Campanularia is defined rd (1959) as hydro an ening rather than a true diaphragm as hy - droid, Hartlaubella is recognized here as a valid genus,

Seasonal Occurrence : Hydroid-- late November through late June,

Known Range: Hydroid--Arctic Ocean to South Carolina.

Family Lovenellidae

Eucheilota ventricularis McCrady, 1857

Eucheilota ventricularis Mayer, 1910b, pa 282, plates 37, 38.

Collection Record: --York River--Gloucester Point plankton sampling station, Description: Hydroid not seen. Medusa nearly hemispherical, reaching 12 mm wide, 7 mm high, mesoglea fairly thick, particularly in the apical region. Radial canals 4, fairly thin, velum broad. Manubrium small, occasionally with 4 interradial black pigment spots visible dorsally, 4 simple perradial lips, gastric peduncle absent. Gonads linear, along slightly more than the middle half of the radial canals. Tentacles filiform, often 20 or more, each arising from a moderate sized tentacle bulb flanked by lateral cirri, 1-3 rudimentary bulbs between each tentacle-bearing bulb, Marginal vesicles closed, about 8-10 in number.

Remarks: In addition to this Chesapeake Bay record, E. ventricu-

medusae were reported by Mayer (1910b) from HaEpt @ e of the Gloucester Point specimens, there were black areas interradially on the manubrium as in the European species, Ee However, the gonads, tentacle bulbs and manubrium weFe t green, not reddish brown. Although the two species are verysimilar morphologically, Russell(1953)reported development of the gonads to occur early in E. maculata, later in E. ventricularis . Neve~theless, a rigoro'Gs cornpar lion of the tFo der.

Seasonal Occurrence: Medusa--September, October,

Known Range: ~edusa--~rcticOcean to Florida.

Lovenella gracilis Cla~ke, 1882 8, B9 C Lovenella gracilis Clarke, 1882, p. 139, figs. 2 5- 39; Cowles, 1930, p. 330; F'raser, 1944, p. 174, fig. 147.

Collection Records: --York River-- Ellen Island, Perrin, Gloucester Point, Paqe s Rock, Bell Rock. --James ~iver- ton ~lhts. Substrates : tenera, Zostera marina, Sertularia argentea, Crassostrea virginica, Crepidula fornicata shells. P

Description: Colony with monosiphonic hydrocaulus reaching 3 cm high, slightly branched or unbranched, divided into internodes by trransverse septa at more or less regular intervals, typical annulations absent except on the hydranth pedicels and at the base of the stem. Hydrothecae alternate on short pedicels, about 600s high, 300ywide, operculum a folded continuation ofthe hydrothecal wall, lacking a hinge-like base, with about 8 facets when folded, tentacles 14, often more, lacking a basal web. Diaphragm thin, with a relatively large basal chamber, Gonothecae clavate, 1.2 mm long, 0.25 rnrn wide, truncate terminally, bornenear the base ofthe hydrothecal pedicels, several medusa buds in each.

Nematocysts : basitrichous haplonemes or microbasic mastigophores . . . . . ,lo-12 x 2.5-3 p (undischarged) At liberation, medusae 0.45- 0.50 mm high, 0.50- 0.55 mm wide. Viewed laterally, medusae hemispherical with flattened sides; viewedorally, medusae oval in outline, being wider in a line through the gonads. Radial canals 4, narrow, velum wide, manubrium short, marginal vesicles 4, closed, each with one concretion. Tentacle bulbs 4, alternate 2 bearing tentacles, and with lateral cirri beside tentacle-bearing bulbs only. Gonads present midway only on two radial canals leading to tentacle-bearing bulbs, Mesoglea. thin, mouth simple, nematocys ts scattered over the exumbrella. Gonads, tentacle bulbs and manubriwn pale straw-colored. Changes occurringwithgrowthunderlaboratoryconditions as follows:

--2 days. Two tentacles absent at liberation developed. Medusae 0,75 mm wide, 0.65 mm high. --4 days. Lateral cirri appearing beside two recently developed tentacles. Medusae 1.0 mm wide, 0.8 5 mm high. --6 days. Four tentacles equally developed. Medusae 1.4 mm wide, 1.2 mm high. --7 days. Eight adradial closedmarginalvesicles present in addition to 4large interradial vesicles, all containing one concretion, --10 days. Interradial tentacle bulbs and tentacles beginning development. Medusae 1.7 mm wide, 1.2 mm high. Nematocysts : basitrichous haplonemes or microbasic mastigophores large ~~e~~~~~~~~~~eee000000e9B5-1P.5x 3-4 p (undischarged) small.,,,...... meseBBBBODm7B559Box 2-2.5 p (undischarged)

Of 20 medusae cultured, only two lived longer than 10 days, --11 days, Interradial tentacles developed, one specimen developing adradial tentacle bulbs. --13 days. Gonads still 2, but medusae round in shape due to size increase. Mesoglea thin, velar opening large, --15 days. Marginal vesicles about 20, one vesicle with 2 concretions. One medusa with 8 tentacles, the other with 14, having 5, 3, 4, 2 tentacles in respective quadrants, Medusae 2,O mm wide, 1.3 mm high. 20 days. Medusae 2.3 mm wide, 1,6 mm high. -7-5 D No morphological change, medusa with 8 tentacles pre- w- served. --27 days. Remaining specimen developing 2 additional gonads. Me- dusa 3.0 mm wide, marginal tentacles 20. 30 days. Medusa everted. Marginal vesicles 23. --T-7 Medusa with 4 gonads, 21 tentacles, 33 marginal vesicles, preserved.

Remarks: The name Lovenella gracilis was given by Clarke (1882) to a hydroid and it edusa from Chesapeake Bay, yet Clarke was not f t was specifically distinct from the European L. Fraser (1910, 1912) used L. clausa forspecimensfrom To d, North Carolina, and NewpoFt, Island, but after e additional material later, convinced that L. s aseparate species (Fraser, 1944), Unlike the Europza the operculum of L. gracilis lacks a definite base s of a folded coEtinuation of the hydrothecal wall rather than separate segments. Fraser (1944) was either in error in reporting a definite base for each opercular "segmenttT or his specimens were unlikethosefrom Chesapeake Bays Intheoriginal description of the species, Clarke (1882) did not mention a definite base, and his figures also indicate its absence. The first European record of the hydroid L. (1952) from the French Mediterranean, aEd distinct from L. ~uvdbelieved that hydromedusa deTcr Brooks (1882) from actually the medusa of L based on similarities between the descriptions by BrT rke, This link was not verified by rearing of medusae from the hydroid, and ~uve'did not find the medusa in Europe. In 1967, laboratory studies were begun to elucidate the organism's life history, Hydroids used in life history work were collected from oyster shells by dredging at page's Rock on the York River, Virginia. Specimens with gonophores were placed in petri dishes containing filtered seawater. Liberated medusae were transferred to 250 ml Erlenmeyer flasks containing 175 ml of filtered 21.5 o/oo seawater and agitated using a Burrell wrist- action shaker. Waterwas changed daily, and medusaewere examined, then fed pieces of enchytraeid worms. Attempts at feeding young medusae the following org.anisms were unsuccessful: Artemia nauplii, larvae, Bankia gouldii trochophore re begun in a constant-temperature roo but, due to mechanical failure of the cooling system, had to be removed to an air-conditioned room after five days. Temperature variation in the room was 20 + 1 C as determined by a maximu-n- minimum recording thermometer.7lthough life history work should be repeated to more adequately describe the older medusae, specimens raised in this study from the hydr indistinguishable from Brooks (1882) their development, and I concur with Hu probably conspecific. To rectify the problem of synonymy, Huve resurrected Brooks' genus Bipleuron, claiming that Lovenella need not be retained as a generic name, He based this the fact thatRussell (1936) had linked the type hydroid of the genus with the medusa Eucheilota Lovenella are not con own to be a the name L. e species b and others. arlier, Mayer Dipleuron parvum to a variety of g on the fewer num medusae differ from Lovenella in having a definite rat vesicles, medusae reared to an monstrate that the organism is a ust be considered a junior of the hydroid and medusa escription of the hydroid having priority over h rooks (1882) account of the medusa which appeared in March, A number of other hydrozoans resemble Lovenella gracilis to some extent in one stage or another, but th on- ship is presently uncertain due to the paucity of information available on the life histories, Stechow (1914) described a hydroid which is at least superficially simila RiodeJaneiro under thename in this species is evident

lacked an operculum. Nutting (1915) also collected and figured the species but did not show an operculum or mention it in the description. Either the link between hydroid and medu$a is in error, or the operculum of the hydroid was lost, as Huve (1952) suggested. Nutting found his specimens on the clam damage and loss ofthe operculum is a possibility, medusa was placed in the genus Eucheilota by Mayer (1 Kramp (1961). In describing L. from Chesapeake Bay, Clarke (1882) did not record the-ex ion or substrate. Cowles (1930) stated it wasknown from the Fortwoolregion, evidently referring to Clarke's report. Wile several of Clarke's hydroids were from Fort WOOL, others were not, andtheassumption should not be made that L. gracilis was found there. Fraser (1944) included the recorz f rea only as Chesapeake Bay.

Seasonal Occurrence : Hydroid--late April through late October. -July through October.

Known Ranqe : ~~dr.6id--Massachusettsto North Carolina and Mississippi. -Chesapeake Bay to North Carolina,

Family Phialellidae

Opercularella pumila Clark, 1876

Collection Records : York River--Gloucester Point. r--SewellPs Point Spit, Sewell's Point, Hampton -- Bar, Hampton Flats, Middle Ground, Nans emond Ridge, Brown Shoal.

Description : Single pedicels or hydrocauli arising from the stolons, branches often present, irregular, colony reaching 5 mm high. Hydrocauli and pedicels wrinkled or corrugated throughout, hydranth pedicels short. Hydrothecae turbinate, 300-364 p long, 145-165 p wide, operculum a folded continuation of the hydrothecal wall with about 8 facets, diaphragm thin. Hydranths with about 14 tentacles, basal web absent. Gonophores fixed, gonothecae f usif orm, 496- 589 y long, 185- 218 JJ wide, pedicels short, annulated, borne on the stolon or stem.

Remarks: Other than the present Chesapeake Bay record, 0. pumila is known from onlyfour locations on this coast. It was ?Yes by Clark (1876) from Portland, Maine, and Montauk Point, Long Island, New York. Specimens were found near Woods Hole in March 1908 by F. B. Sumner and discussed briefly by Hargitt (1909) and by Sumner, Osburn and Cole (1913). Fraser (1918) obtained specimens at St, Andrews Island, New Brunswick. Berrill (1949) described the developmentandmorphology of the species but did not mention the collection locale of his specimens. It was also reported in WHO1 (1952) to foul buoys but without location records. Nutting (1901), who did not collect the species or observe the types, expressed doubt that it was different from 0. lacerata, a more widespread and,r.e.latively common species. Hargytt ) specimens of 0. pumila and those from Chesapeake Bay conform with Clark.Ps ds-cri-ption and, as such, are distinct morphologically from 0. lacerata. Fraser (1918)felt the twoweredifferent beyond qu e s tYon ost distinguishing feature is the shape of the gonothe-cae, those of 0. being oval or cylindrical, those of 0. pumila being fUsi a tubular distal end. Fraser fouEd TEFVdrothecae tobeabout half as long in 0. pumila (0.25 mm) as in 0. lacerata (0.45 mm). Hydrothecae of~speT~m~sfrom Chesapeake-Bay are comparable in size (0.30 mm) with ~raser's0. from St. Andrews. 0. is usually much less branchFd bay as both branched and un-

is rather inconspicuous due to its size, o overlook in Hampton Roads where it was ecially on Sertularia -argentea, Seasonal Occurrence: -late September through late May. es--mid-December through mid-Maye

Known Range: ~~droid--~ewBrunswick to Chesapeake Bay.

Family Phialuciidae

Phialucium carolinae (Mayer, 1900)

Collect ion Record : --York River--Gloucester Point plankton sampling station. Description : Hydroid not seen. Medusa hemispherical, reaching 9 mm wide, 5 mm high, mesoglea thick, notably in the apical region. Radial canals 4, thin, velum moderately thin. Manubrium small, quadrate, with 4 drawn out and slightly crenulated lips, gastric peduncle absent. Gonads linear, along distal third of the radial canals. Tentacles about 8-16, f ilif orm, arising from moderate sized tentacle bulbs with excretory pores, lateral cirri absent. About 4 closed marginal vesicles between successive tentacles.

Remarks: This medusa, occurring in late summer at Gloucester Point, has not been reported north of Cape Hatteras previously. Mayer (1910b) found it in great abundance in Charleston Harbor, South Carolina, during early September 1897 and in June 1898.

Seasonal Occurrence: Medusa--August, September.

Known Range: Medusa--Chesapeake Bay to the Caribbean Sea. Incertae Sedis Blackfordia- virginica Mayer, 1910 Blackfordia virginica Mayer, 1910b, p. 277, plate 36; Kramp g, 210; 1961, p. 181. Blackf ordia virginiana Cowles, 1930, p. 331. --- -A , Remarks: Although this medusa was originally described from Virginia by Mayer (1910b), it was not identified during this study. Mayer found an abundance of the medusa in Hampton Roads and Norfolk Harbor during October and November of 1904. Cowles (1930) reported it as B. virginiana from Chesapeake Bay, and Cronin, Daiber, and ~ulbert(1962) found it sporadically in Dela- ware Bay during summer,

Kramp (1958) examined B, ' a medusae from Norfolk Harbor, the Black Sea, and th? G ary, and was convinced that all belonged to the same species. He believed that further study might show B. a similar medusa described from New Jersey by MayFr be identical with B. Valkanov (1935), who found the medusa in the Black Sea, its hydroid as a Campanulina bearing a web at the base of the tentacles,

Known Range: Medusa--Delaware Bay to Chesapeake Bay,

Collection Record: --York River--Gloucester Point. Substrates: Halichondria bowerbanki, Hydroides hexagona tubes, -Crassostrea virginica Description: Zooids about 1.0-1.5 mm high, arising singly from a stolon network, elongate, somewhat bulbous below the tentacular ring. Hypostome dome-shaped, tentacles about 16, f iliform, in a single whorl, web absent. Perisarc thin and loose about the stolons, terminating a short distance up the zooid- Gonophores not seen,

Remarks: The identity of this tiny hydroid was never determined since medusa buds or medusae were never seen. As a result, practically nothing is known regarding its systematic position. The hydroid was collected sporadically from July to November, but this may not be an accurate indication of its seasonality as it is easily overlooked. Specimens from Gloucester Point were examined by Dr. K. W. Petersen, who suggested it might be a "Campanopsis," the hydroid of a eutimid medusa, Complete life ies willbenecessary to elucidate the exact identity of this organism. "Campanulina" sp, 1 P

Collection Record : York River--Tue Marsh Light. P-- Substrate: Rock.

Description : Colony consisting of hydrocauli with several hydrothecae, or single hydrothecae arisingbypedicels from the stolon. Colony reaching 5mm high butusuallyshorter, pedicels and hydrocauli annulated throughout. Hydrothecae cylindrical with square base and pointed tip, about 500 JI long, operculum a folded continuation of the hydrothecal wall, with fine longitudinal striations, facets indefinite, Hydranth with about 16 tentacles lacking a basal web, Gonophores not seen,

Remarks: This hydroid was seen only once, on 14 August 1967 in 3 m of water at Tue Marsh Light, In overall colony shape, the specimens resembled hydroids identified as "Campanulina '' sp . 2, but the hydranths had fewer tentacles (about cked the web at the base of the tentacles,

"Campanulina " sp . 2 PEt' late 8, E

Collection Records : York River--Page ' s Rock, Bell Rock. iver--West Point, P-35. ig Point, Bennett" Creek, Deep Water Shoal, og Island. Nansemond --River--Newman 's Point,

Description: Colony consisting of a stolon network with single hydrothecal pedicels or hydrocauli with 3 or 4 hydrothecae. Length of fully extended hydranth about 700 p, diameter 100 p. Maximum colony height about 2.5 mm, usually shorter. Tentacles 20-21, about 600 y long, united for 1/4 their length by a web. Hydro- thecae cylindrical, about 500 p long, base square, tip pointed, operculum a folded continuation of the hydrothecal wall, Perisarc imperfectly annulated. Gonophores producing medusae, Gonothecaearisingvia a short imperfectly annulated pedicelfromthe stolon or hydranth pedicel, obconic, height about 600 p, width 200 p, one medusa per gonotheca. Gonothecae collapsing on release of medusae but later regaining original shape, Hydroids whitish in life. Newly liberated medusae bell-shaped, with 4, occasionally 3, well developed perradial tentacles and 8 closed adradial marginal vesicles, each containing one concretion, Primordia of 4 additional tentacles present interradially. Mesoglea very thin, medusa height and width 0.5 mm, nematocysts scattered over the exumbrella. Radial canals narrow, 4, ring canal and well developed velum present. Manubrium about 0.2 mrn long, mouth with 4 simple lips. Gonads absent, Medusa colorless except for golden-yellow manubrium and tentacle bulbs,

Remarks: The hydrozoan genus Campanulina van Beneden, 1847 was erected for C, webatthe base of the tentacles bu'F n an operculum. Additional species later added to the ge ded a number of heterogeneous hydroids whose medusae often were placed in different genera or families. In a revision of the genus, Rees (1939) retained Campanulina solelyforc. sincenone ofthe otherspecieswerecongeneric with it. Erl incks (1868) had with fixed gonophores to a new genus, nized this genus and placed other medusae in a number of other genera Campomma, Eirene and ella, 5555s of a "Campanulina-type1' hydroid were found in samples fromthe Pamunk rginia, during August 1965 and were collected at frequent intervals from several locations inthe State from then until 1967. In July and August 1967, colonies withmedusabuds were obtained, but attempts to raise the liberated medusaewereunsuccessful and the identity oftheorganism remains in doubt, The hydroid was common inwaters of reduced salinity in both James and York rivers, Virginia, It reached peak abundance in the autumnand evidently became dormant inmid-winter, reappearing in spring. Medusa buds were observed only in July and August, While the species may be local, more likely it has been overlooked in collections elsewhere since the hydroid is relatively small. Possible restriction to reduced salinity waters may be partly responsible since this environment has received less attention than marine or freshwater habitats.

Family Eutimidae

Eutima mira McCrady, 1857 87

Collection Record: Chesapeake -Bay--Kiptopeke. Description: Hydroid not seen. Medusa umbrella-shaped, bell 8 mm wide, 5 mm high, mesoglea of moderate thickness. Radial canals 4, velum broad. Manubrium small, quadrangular, with 4 folded lips, borne on a long gastric peduncle reaching considerably beyond the velar opening, Gonads linear along radial canals and along the proximal portion of the gastric peduncle, sinuous along the remaining portion, Tentacles 4, f iliform, large, epithelium compactly folded, being smooth only near the attachment to the umbrella, Margin with numerous small warts and about 8 closed marginal vesicles ,

Remarks: Severalspecimens of E. mira were found in aVIMSplankton sample collected by meter net-o October 1961, Mayer (1910b) reported themedusa commonat Beaufort, North Carolina, Charleston, South Carolina, and Tortugas, Florida, Mayer also collected it occasionally at Newport, Rhode Island, and Woods Hole, where it was rare some years and abundant during others. This report constitutes the first Chesapeake Bay record of the species.

Known Range: Medusa--Massachusetts to Florida,

Family Sertulariidae

Dynamena cornicina McCrady, 1857

Collection Records : York River--Tue Marsh Light, Perrin, Gloucester Point, -- Page's Rock. James River- -Hampton Bar, Bay--Little Creek Jetty, Cape Charles,

Substrates : Rubber hose, rubber tire, wood pilings, asbestos fiber test panels, metal oyster trays, Agardhiella tenera, Champia parvula, Zos tera marina, Mytilu

Description: Colony consisting of anupright, monosiphonic hydrocaulus reaching 5 cm high, usuallyless, typically unbranched but occasionally with one branch given off at an angle of somewhat less than 90". Hydrothecae sessile, 2 per internode, strictly opposite, cylindrical, adnate for about half thei-r length in front, widely separated but parallel in back, turned abruptly outward. Hydrothecal margin with two distinct lateral teeth and a small median adcauline tooth, operculum of 2 valves, the smaller adcauline valve divided into 2 parts by a line running from the median adcauline tooth. Hydrothecae with prominent perisarcal projections extending from the base. Abcauline caecum absent, Entire colony bright yellow. Gonophores fixed, gonothecae usually borne on the stolon but occasionally on the hydrocaulus from an old hydranth, gonothecae oval, rugose, terminal aperture large.

Remarks: Usually this species is relatively small, but Fraser (1944) found robust specimens of Dynamena from the west coast of Florida identical to D. cornicina in all other morphological respects and concluded That it was the same species. The typical small form reaches 1.5 cm in height, while the robust form found by Fraser reached 5 cm. In Chesapeake Bay, D. cornicina colonies normallyrange insizefrom 1 cm to 5 cm, VerVoo escribed pinnate specimens fromtheRed Sea and Gulf of Aqaba ranging from 3 cm to 10 cm in height. Though colonieswereusually unbranched, inexceptional cases branching was noted but nomore than one branch per stem was ever observed. Branching was unlike that described by Vervoort (1962) for the pinnate forms, The branches in Virginia specimens arose from a point where a hydrotheca would normally have occurred. No axillary hydrothecae were present and on both stems and branches the hydrothecae were strictly opposite. This species was abundant during summer in the lower bay, particularly on eelgrass.

Seasonal Occurrence: Hydroid--late April through mid-November. es--mid- June through late September,

Known Range: Hydroid--Massachusetts to the Caribbean Sea,

Sertularia argentea Linnaeus, 1758

Thuiaria argentea Cowles, 1930, pe 330; Fraser, 1944, p. 293, ey, 1946, p. 86. (sic) Ferguson and Jones, 1949, p. 438. ea Calder and Brehmer, 1967, p. 153,

Collection Records: Rappahannock River--Hogge House Ground. sh Light, Ellen Is land, Gloucester pp Point, Page's Rock, Y-20. James River--X-Ray Station, Sewell's Point Spit, Sewell's PP Point, Hampton Flats, Hampton Bar, Norfolk Navy Base Pier 12, Middle Ground, Newport News Bar, Nansemond Ridge, Brown Shoal, Deep Water Shoal,

Chesapeake 7Bay--Cape Charles, Cherrystone Channel, Kiptopeke Beach, Chesapeake Bay Bridge- Tunnel, Thimble Shoal, Willoughby Bank.

Description: Colony consisting of a monos iphonic hydrocaulus reaching 35 cm or more high, branches arising from all sides in a regular arrangement. Branches dichotomous with a hydrotheca in each axil. Hydrothecae sessile, alternate, quite distant, fusiform, being widest in the middle, somewhat less than half of the adcauline wall free, distalportioncurved gradually outward, but hydrothecaefacingupward, Operculum of 2 valves, 2 prominent teeth, abcauline caecum present, Gonophores fixed, gonothecae arising from the upper surface of the branches near the base of the hydrothecae, arrow-head shaped with one or two prominent shoulder spines distally and a short collar bordering the terminal opening.

Remarks: During winter, S, argentea was the most abundant hydroid on sandy and shelly boyto haline waters of Chesapeake Bay* With increasing water temperatures in spring, hydranths regressed, smaller branches were broken off, and by mid- and late- summer the only remnants were the long, tough main stems, In autumnas temperatures dropped to 20 C and below, new growthbegan from tissue in the old stems, hydranths were formed, and growth proceeded rapidly. Reproduction, development and growth in this hydroid have been well studied and described by Hancock, Drinnan and Harris (1956) from Thames estuary material, There has been considerable taxonomic confusion over the relationship between S. The two were described as separatF , but later Linnaeus (1767) placed cupressina. Some subsequent stude asseparate species, including Hincks (1904), von Reitzenstein (1913), Fraser (1944), and additional authors, while others have united them as one species, S. (Broch, 1918; Kramp, 1938b; Leloup, 1938 ; Vervoort,-19 1960), Broch (1918) felt that the characters uponwhich separation was based were too variable to be used as indicative of specific differences . Hancock -et al, (1956) presented evidence indicating the two were distinct, parEcularly inthemanner of branching. Based on their research, the two species are considered separate here. In addition to confusion over the species problem in this case, these organisms have been placed in either of two genera, (on rare occasions in19th century litera- As these genera are distinguished by the having one and t belong to the es, However, Fraser (1944) and others, following a modified description of by Allman (1874), placed S. ria, Under Allman's criterra, e alternate or subopposite i Allman's etwith little acceptance, an revision of the sertulariangenera is made, thetwo species belong inthe genus Sertularia.

Seasonal Occurrence: Hydroid--late September through mid- June, es--early November through mid-May.

Known Range: ~~droid--~rcticOcean to North Carolina, Louisiana, Family Plumulariidae

Schizotricha tenella (Verrill, 1874) G

Schizotricha tenella Calder and Brehmer, 1967, p. 153,

Collection Records : Rappahannock River--Hogge House Ground. rsh Light, Gloucester Point, Page's Rock, r--SewellPs Point Spit, Sewell's Point, Hampton PP Bar, Hampton Flats, Norfolk Navy Base Pier 12, Middle Ground, Nans emond Ridge. Chesapeake Bay--Willoughby Bank, Cape Charles, Little Creek -- Jetty.

Substrates : Brick casing, rope, wood pilings, metal oyster trays, test panels (asbestos fiber, acrylic plastic), glass bottle, Zostera marina, Halichondria bowerbanki,

9 manhattens

Description: Hydrocaulus monosiphonic, reaching 10 cm high, hydrothecae and nematothecae often absent for a short distance basally but present elsewhere, Hydroclad ia given off alternately, themselves of ten alternately branched. Hydrocladia typically made up of a series of three nodes: a short athecate internode lacking nematothecae, with nodes transverse at both ends ; a longer athecate internode with node transverse proximally, oblique distally, 1- 2 medial nematothecae ; a thecate internode, node oblique proximally, transverse distally, with a median inferior nematotheca and a pair of lateral nematothecae; short atheeate internode occasionally absent. Hydrothecae cup-shaped, margin entire, borneona projection of the internode, about half of the adcauline wall adnate, Nematothecae all bithalmic and movable. Gonopho~esfixed, gonothecae cornucop ia-shaped, arising from the hydrocaulus at the origin of a hydrocladium or on the hydrocladia at the base of a hydrotheca or branch.

Remarks : Millard (1962) reviewed the systematics of the family Plumulariidae and erected a new subfamily, the Halopterinae, to which Schizotricha tenella belongs. The subfamily is distinguished from Eerinae, Plumulariinae and Aglaopheniinae by the presence of cauline hydrothecae on pinnate stems. Though Vervoort (1968 ) retained S . he noted that it is similar to and probably identicalmw teris diaphana , S, tenella was one of the s in the lower bay drring summer, covering ropes, pilings, and similar substrates from MLW to the bottom in shallow water. Colonies up to 10 cm in height were collected at Gloucester Point, twice the maximum height recorded by Fraser (1944), Fig. 2. Oral view of Maeotia s inexpectata . Medusa 45 mm wide. Seasonal Occurrence : Hydroid--.early May through early December. es--late May through mid-October.

Known Range: Hydroid--Massachusetts to the Caribbean Sea,

Order Limnomedusae Family Olindiidae

Maeotias inexpectata (Ostroumov, 1896)

Maeotias inexpectata Calder and Burrell, 1969, p. 694.

Collection Records: Pamunkey River--P-30, P-40.

Description: Hydroid not seen. Medusae saucer-shaped, 20-45 mm wide, mesoglea thick, Radial canals 4, fairly wide, 11-20 wide centripetal canals of varying length per quadrant, occasionally with short diverticulae, velum wide. Manubrium large, quadrate, with 4 very long, pointed, frilly lips. Marginal tentacles filiform, of one type, hollow, many broken off near the base, numerous (300-550), not in definite rows, terminating in a cap of nematocysts, in rings elsewhere. Margin with about 175-300 marginal papillae, 200 or more closed marginal vesicles, Gonads 4, extending alongthe radial canals nearly tothering canal. In formalin- preserved specimens, marginalpapillaeintense salmonto orange-red, radial and centripetal canals similar color but less intense.

Remarks: This species appears to be another example of a medusa indigenous tothe Middle East now occurring inmeso- and oligohaline waters of Virginia. Known elsewhere only from the Black Sea and Sea of Azov, it was reported in Virginia by Calder and Burrell (1969). Specimens were collected in trawl samples during October and November 1968 in salinities from 4.16 o/oo to 10.66 o/oo.

Order Trachymedusae Family Geryonidae

Liriope tetraphylla (Chamisso and Eysenhardt, 1821 ) Plate 8, G

Liriope scutigera Brooks, 1886, p, 373, plates 41, 42; Cowles,

Mayer, 1910b, p. 421, plate 50, yer, 1910b, p. 419, plate 51. ramp, 1961, p. 238. Collection Record: --York River--Gloucester Point plankton sampling station. Description: Medusa umbrella-shaped, reaching 7 m wide, mesoglea thick apically, thinner laterally, Radial canals 4, wide, centripetal canals present, velum well developed. Manubrium small, quadrate, on a gastric peduncle of variable length, but extending well beyond the velar opening. Gonads 4, large and leaf-shaped, on the radial canals. Four large perradial and 4 small interradial f iliform marginal tentacles,

Remarks: Numerous species of Liriope have been described, but it is now generally agreed t represent one species, -L. is probably not autochthonous to Chesapeake support this may be found in its absence from the planktonat Gloucester Point during 1967, whereas during late summerand early autumn of 1966 medusae were very abundant. Kramp (1959) regarded L. as anoceanic ratherthana neritic species, Appearaiice romedusa in the bay would then be dependent upon off s s and the factors, including wind and runoff patterns, which determine the water circulation. Harrison (1967) found evidence for a July 1964 inshore meander o Gulf Stream, and a shoreward spiral of warm surf ace, or near surface, water along 37"00WN. Indications were that the sh0rewa.d spiral continued during August 1964 as well, Such a circulation pattern could carry offshore species toward and into the bay, Coincident with the absence of L. in the 1967 plankton, Gail Mackiernan (personal coEm oted an absenceof certain offshore dinoflagellates that had been present at Gloucester Point in 1966.

Seasonal Occurrence: Medusa--August through November.

Known Range : Medusa--Gulf of Maine to the Caribbean Sea,

Family Rhopalonematidae

Aglantha digitale (0, F. MGller, 1776)

Aglantha digitale Cowles, 1930, p, 331; Kramp, 1961, p, 248,

Collection Record : Chesapeake Bay--Station C-00.

Description: Specimens reaching 7 mm high, cone-shaped, mesoglea very thin except for a small apical dome, Radial canals 8, fairly wide, velum well developed. Manubrium small, quadrate, borne on a long peduncle but not reaching the velar opening, Gonads 8, elongate, hangingfromthe radial canals near the apex. Tentacles broken off, condition of medusae too poor to determine the nature of the marginal sense organs,

Remarks : A few small specimens of A. digitale were found in a sample fromtheVIMS plankton collectTo 3 March 1961 with a Gulf I11 plankton sampler. The specimens were readily Sdenti- f iable but in rather poor condition. The medusa was earlier reported in Chesapeake Bay by Cowles (1930).

Known Range: Medusa--Arctic Ocean to Chesapeake Bay.

Order Narcomedusae Family Cuninidae

Cunina octonaria McCrady, 1857

Cunocantha octonaria Brooks, 1886, p. 361, plates 43, 44.

Collect ion Record : --York River--Gloucester Point plankton sampling station. Description : Actinulae parasitic on Turritopsis nutricula medusae, attached by 4 tentacles to the s elongate throat-tube present, Medusae saucer- shaped, reaching 3 mm wide, umbrella margin with 8 lobes, mesoglea of moderate thickness, Radial canals and ring canal absent, gastrovascular cavity with 8 square pouches, manubrium wide but short, often folded, velum well developed, Marginal tentacles 8, large, filiform, arising at the distal end of the marginal pouches. Marginal sense organs 1-3 per octant, tentacle-like . Remarks: In early autumn of both 1966 and 1967, C. octonaria medusae were common in the plankton at Gloucester Poynt of ten parasitic on other hydromedusae, were frequently seen on Turritopsis nutricula, The unusual life history of this organism ed by Brooks (1886).

Seasonal Occurrence : Medusa--September, October,

Known Range: Medusa--New Jersey to the Caribbean Sea. ERRONEOUS OR DOUBTFUL RECORDS

CowlesP (1930) coverage of the Chesapeake Bay Hydrozoa was insufficiently documented and evidently contains much erroneous information. Nutting (1901) is purported by Cowles to have described Thuiaria argentea, T. cupressina and T, plumulif era from s Role region, and no apeake Bay. Further, paper at all, Nutting ort it, but from shelf waters off Chesapeake Bay,

was obtained by Cowles States National Museum, Again, these records may be for coastal waters and not for the bay. All of the above, except A. and "near alternata, " were identified by 'Wut eve (1900, , 1915) did not report any of them from the bay, although several were found offshore in shelf waters, Fraser (1944), who had the collection of the United States National Museum at his disposal, did not report any of the above except ( ) from inside the Chesape s identified by VIMS perso 1959 is given in Table 5, The only specimens available from that collection were those identified as

the latter were for verif icatio

occur in the bay,

, as discussed earlier. species on the VIMS invertebrate check list

at Gloucester Point were examined

6) from test panels

les (1930) included two provisionally identified specimens, Bougainvillia ramosa and Table 5. Hydroids reported from the Virginia Institute of Marine Science (Virginia Fisheries Laboratory) collection up to 1959,

Date of Identified Species Collect ion Locat ion BY

Svncorvne mirabilis August 1958 VFL Ferry Pier, York River Bougainvillia rugosa 21 August 1958 VFL Ferry Pier, York River Bougainvillia inaequalis July 1957 Ferry dock pilings, Gloucester Point Pennaria tiarella July 1957 Eelgrass, VFL beach 29 July 1958 Hampton Roads Bar W. G. Hewatt Clvtia cvlindrica 29 July 1958 Hampton Bar - 28 July 1958 New Point Comfort ecta August 1957 Ferry dock pilings, Gloucester Point Plumularia diaphana 28 July 1958 Hampton Roads Bar W. G. Hewatt August 1958 VFL oyster trays, Gloucester Point Thuiaria argentea 19 June 1958 Station B-9, W. G. Hewatt York River Thuiaria cupressina 26 June 1958 Cape Henry, Va. W. G. Hewatt (100 fathoms ) Sertularia stookeyi July 1957 VFL beach, Gloucester Point Halecium beani 29 July 1958 Hampton Bar, W. G. Hewatt Hampton Roads, Va. Liriope scutigera, Liriope scutigera is now considered synonymous oes occur in Chesapeake Bay, he nearest previous record of three North Carolina, 9 Aglaura hemistoma and Rhopalonema velatum, as - Chesa em from collections by Bigelow (1915, 1918) and were for the shelf waters offshore. Bigelow's (1915) closest station tothe bay entrance was 37"00rN9 75'38'~~while his closest station recorded inthe1918 paper was 36' 12'N, 74' 25 'We PHENOLOGY AND ZOOGEOGRAPHY

Southern Chesapeake Bay is characterized by extreme seasonal differences in water temperature (Fig. 3) and a somewhat less pronounced salinity variation (Fig. 4). These conditions are unfavorable to stenotopic species and all the hydrozoans studied here presented a distinct seasonality. From their seasonal occurrence, Chesapeake Bay hydroids can bedivided basically into a summer fauna and a winter fauna. Of the 23 species for which adequate seasonal data are available, 16 may be regarded as summer species and seven as winter species, The greatest number of species occurred in May when 21' of the 23 species were recorded, the fewest in February and March when only eight were found. May- June and November-December were the intervals when faunal change was most pronounced and during these periods overlap of summer and winter forms was greatest. Seasonal distribution of fixed gonophores and medusae was even more restricted. None of the medusae whose seasonality was studied occurred in the water throughout the year. Maximum numbers of species and individuals occurred during summer and autumn, while fewest were present in winter, From observations on the influence of temperature on seasonality, it might be assumed that a species would occur at different times of the year in different latitudes. While this may be true in some cases, with the boreal species Aselomaris michaeli and being typical winter f apply* At Woods Hole, Hargltt active hydroids of Halocordyle from June untilNovember. In Chesapeake Bay, it is presen une through October, and while colonies of the species were expected and specifically looked for prior to June, collections before that month yielded only dormant stolons. At Beauf ort, McDougall (1943) reported He disticha active from mid-April until late November. ObeliZ one of the most cosmopolitan of all hydroids, occurs as asummer species in Chesapeake Bay, not havingbeenfound below 15 C, yet it is known as far northward as Labrador and Hudson Strait (Fraser, 1944) where temperatures never reach 15 C. This also demonstrates that a species may not tolerate within a given area the range of temperature that it tolerates geographically, and that seasonality in a given area cannot always be predicted from its temperature tolerance or seasonality in another region. Numerous references in the literature state that crocea does not remain active in temperatures above 20- owever, T. crocea was healthy, abundant, and reproducing at on rock -1s nd pilings of the Chesapeake Bay Bridge-Tunnel and on pilings along the southern bay shore of Northampton County, Virginia, during summer 1967. McDougall (1943) also found that 20 C was not the critical temperature for autotomy in -T. crocea

at Beaufort. He believedthatsuccessive summer generations showed increased tolerance forhigh temperatures compared with winter and spring*generations. Populations present during July and August survived temperatures up to 30 C. Obviously, a species may not occur inanarea although temperature may be seasonally favorable. While the wide range of temperature in Chesapeake Bay makes it theoretically possible, considering temperature alone, for a large number of species to occur, at least seasonally, the fauna of the bay is typically that of the temperate zone. Factors other than temperature may play a role in hydrozoan seasonality. Brinckmann (1964)noted that colonies of Staurocladia kept at constant temperature for a year exhibited a definite seasonality both in activity and in production of medusa buds, and Barth (1940) showed that oxygen concentration influences hydroid regeneration. In Chesapeake Bay, however, seasonality correlates very well with water temperature, undoubtedly the primary factor in the annual hydrozoan activity cycle (Calder, 1967). Chesapeake Bay is an interesting region for zoogeographical comparison with other regions because of its wide range of environmental conditions from location to location and from season to season. The baydoes not correspond readily with any ofthe proposed zones delineated on the basis of temperature since temperatures may vary in extreme cases from 0 C in winter to 30 C in summer. Among the several zoogeographical divisions ofthe Atlantic coast, one of the better knownis that of Stephensonand Stephenson (1954). Included in their scheme were the following provinces:

1) Arctic, with a southern limit probably lying north of Labrador 2 ) Subarctic or Syrtensian, including Labrador, most of Hudson Bay, the southern tip of Greenland, northern Newfoundland and the Gulf of St. Lawrence 3) Acadian, extending from Cape Cod northward to the Subarctic 4) Carolinian, extending from Cape Hatteras to Cape Kennedy 5) Tropical, from Cape Kennedy southward

The Virginian, extending from Cape Cod to Cape Hatteras, was not consideredadistinct province but an overlapping region with some Acadian forms and some Carolinian forms. A comparison of the hydroids inthe Acadian with those of the Virginian indicates that Cape Cod is not a significant barrier to hydroid distribution (Table 6). However, Cape Hatteras appears to be a more effective breaking point since the Virginian and Carolinian faunas are somewhat distinct. Fraserrs (1944) data suggest a boreal fauna from Cape Hatteras northward to the Mari- time Provinces, anda tropical fauna from Cape Hatteras southward. However, Chesapeake Bay hydroids show a slightly greater affinity with those of the Carolinian Province(Table7). Of these species, Table 6. Zoogeographical comparisons of the hydroid fauna along the eastern United States (data from Fraser, 1944).

Acadian Province Virginian Province

Number of species Percent in common

Virginian Province Carolinian Province

Number of species Percent in common Table 7, List of hydroids from Chesapeake Bay, with their east coast distribution. Presence is indicated by +; (+) indicates record of medusa only,

Acad ian Carolinian Species Province Province

Moeris ia lyons i 70% occur south of Cape Hatteras, while 54% occur north of Cape Cod. Thirty-seven percent of the species occur both north of Cape Cod and south of Cape Hatteras. The various families of hydroids show differing patterns in number of species from one region to another. The Plumulariidae are well represented in the tropics but thin out markedly toward the poles. Fraser (1944) listed 62 species from the Carolinian, 18 from the Virginian and 5 from the Acadians The only representative of the family in Chesapeake Bay is Schizotricha tenella. The number of hydroid species overall doe ny great increase in number of species toward the equator, and Deevey (1350) observed that habitats for hydroids are no more extensive in the tropics than elsewhere, Fraser (1944) listed 129 species from the Arcticandsubarctic, 126 from the Acadian, 153 from the Virginian, 163 from the Carolinian, and 202 from the Caribbean, West Indies, and Gulf of Mexico, Thehydromedusaeof ChesapeakeBayalsoshowagreater affinity with the Carolinian than the Acadian (Table 8), Of these, 74% occur in the Carolinian, while 37% occur in the Acadian. Twenty- six percent occur in both provinces. As presently known, the hydrozoan fauna of Chesapeake Bay typifies the Virginian transitional zone. Unfortunately, seasonality is ignored in such zoogeographic analyses since few records include the dates or season of collection. It seems possible that theVirginian region, characterized bywide seasonal temperature variation, has primarily an Acadian hydrozoan fauna inwinter and a Carolinian fauna in summer, but data totest this hypothesis are not available, There is little doubt that additional species of hydrozoans occur in the bay, particularly in the case of hydromedusae for which an exhaustive study was impossible. With the importance of shipping in the area, notably in the ports of Hampton Roads, introductions aretobe expected. Nevertheless, the hydroid fauna of lower Chesapeake Bay is probably relatively impoverished in terms of species. About half of the families listed by Fraser (1344) fortheAtlantic coast of America were not represented and such large families as the Sertulariidae and Plumulariidae had but one or two representatives each. Whereas 43 hydroid species were identified from the bay in this study, Fraser (1910) at Beauf orY, North Carolina, identified 51 species during a 2-week study. For the Woods Hole region, Smith(1964)included a partial list of 39 species but these were evidently only the more common forms, as ~raser's(1944) data indicate a much richer fauna. The lowdiversityofhydrozoan species inthe bay is attributed to a number of factors, some of which may work in combination, notably temperature and salinity. The shorelines and bottom are predominantly sand and mud, providing unfavorable substrate both for hydroids and organisms which are hydroid substrates, An absence of rocks (except on man-made islands and jetties), tide- pools and heavy algal mats limits substrate and niche diversity. Nishihira (1964) showedthatwhile Chlorophyta support fewhydroids, macroscopic Phaeophyta are especially favorable, and these algae are greatly reduced in the bay. Sargassaceae, particularly Table 8. List of hydromedusae known from Chesapeake Bay and their east coast distribution. Presence is indicated by +; (4) indicates record of hydroid only.

Acad ian Carolinian Species Province Province

ppp---- Moer isia lyons i

ens is rugos a el favorable as substrates, do not grow in Chesapeake Bay, and little is normallycarriedin by currents. Themost common firm substrates for hydroids in Chesapeake Bay included Zostera marina, sponges, other hydroids, mollusk shells, arthropod exoskeletons, tunicate tests and such substrates as rock islands, buoys, rope, concrete blocks, pilings, or other objects of human endeavor, Waters of the bay are turbid, andturbidity intensifies progressively toward the heads ofthe tributaries. Substrates not swept by moderate currents rapidly become covered with silt, making planula settlement difficult. On artificial substrates, such as test panels, competition for space with other epibenthos was noted, particularly during smer when heavy set and rapid growth of the ascidians Molgula manhattensis and Botryllus schlosseri occurred. Although little is known regarding the salinity tolerance of most hydroids, the number of species is probably further reduced under the bay's estuarine conditions.

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Rappahannock River Near R. 0. Norris Bridge Hogge House Ground Waterview Bowler' s Rock Tappahannock --York ~iver Tue Marsh Light Guinea Neck Perrin Ellen Island VEPCO (Yorktown) outfall Off VEPCO (Yorktown) Gloucester Point Pagef s Rock Cheatham Annex Aberdeen Rock Y-20 Bell Rock West Point Mattaponi River Near Indian Reservation Pamunkey River P- 30

--James River Old Point Comfort X-Ray Station Sewell' s Point Spit Sewell1s Point Hampton Bar Hampton Flats Norfolk Navy Base Pier 12 Newport News Bar Middle Ground Nansemond Ridge Pig Point Bennett's Creek Entrance Bennett' s Creek Brown Shoal Deep Water Shoal Lawnes Point Off Hog Island Jamestown Island Elizabeth River Hos~italPoint ~ansembndRiver Newman' s Point N- 13 Chesapeake -Bay C- 00 Fishermanqs Island Chesapeake Bay Bridge-Tunnel Mid- span Virginia Beach span Kiptopeke Little Creek Jetty Cape Charles Cherrystone Channel Willoughby Bank Thimble Shoal New Point Comfort Mid- Bay Station INDEX TO GENEFCA AND SPECIES

Aeauorea 69 aequorea 80 asassizi, Linvillea 9, 12, 17, --28-29, 78, 86, 88 48 digitale 11, 19, --76-77, 88 Aglaophenia rigida 78 hemistoma 80 Eudendrium 10, 13, 45-46, 86

americana, Antennularia 78- ' Amphinema dinema 10, 13, 18, 43-44, 86, 88 antennina, Antennularia 78 -- Antennularia americana 78 antennina 78 - r--.- ' - apicatus, Perigonimus 44 arenosa, Aselomaris 42 arae 4 Hydractinia 9, 13, 18, 31-33, 78, 86, 88 Stylactis 31 -- ~~tlactis31 araentea

Thuiaria 7177~'79 ' argentia, Thuiaria 71 Aselomaris 42 arenosa 42 michaeli 10, 13, 41-42, 81, 86 bachei, Nemopsis 10, 17--T!2-43, 88 Clytia 64 Phialium 64 beani, Halecium 78. 79 bicuspidata, 0belia 10, 15, --53- 54, 57, 58, 78, 86 anciscana 40, 41 tunicata 40. 4: , - Blacktordia tensis 67 virqiniana., 67 virginica 9, 11, 19, -67, 88 Bougainvillea rugosa 36 Bouqainvillia- carolinensis 9, 17, 35-36, 38, 88 inaeaualis 78. 79 -- multicilia 38 multi tentaculata

rugosa 9, 13, 17, 27, --36-39, 49, 55, 59, 65, 71, 79, 86, 88 39, 40 39 17 Campanopsisv 67 ?~Campanopsis" sp. 11, 13, -67, 86

tenuis 69 Campanulinafl 69 sp. 1 11, 16, 68, 86 sp. 2 11, 16, --m-69, 86 Campomma 69 carnea, Podocoryne 78

bakeri64

4 hemisphaerica 10, 15, 48, 49, -50, 86 50 14, 50- 51, 86

51 0, 14, 51- 53, nata? 1 78- cornrnissuralis, Obelia 10, 15, --54-55, 86 conirostris, Lirlope- 7 5

1ac;stri.i 30' -' corn amena 11, 16, --70- 71, 86 Corynetes 29 Corvnitis, 29 costata, Zanclea 9, 12, 18, --29-30, 86, 88 crocea, Tubularia 9, 13, 24-25, 78, 81, 86 17, n,77, 88

, 15, --48-49, 54, 78, 79, 86

11, 19,76-77, 88 10, 13, 1- --m-44, 86, 88

26-27> 86, 88 9, 12, 18,7536, 32, 81, 86, 88 ,73Z4,-- 25, 51, 59, 78, 86, 88

actinia 971T 33-34, 78, 86 9, 13, n,T3-24, 25, 51, 59, 78, 86, 88 14, --49-50> E

cimalis 64

maculata 61 ventricularis 10, 19, -61, 88

-- carneum 9, 10,-T4746, 47, 86 ramosum 10, 14, 46-7, 65, 86 Eutima mira 11, 19, --69I7T 88

cerulea 10, 14, 39-40,86 -fFamcana 10, f4,-P40-41, 86 50, 53,T8,78

artlaubella 10, 15, 48, --60-61, 65, 86 loveni 10, 15, 4 dosa 64 gracile, Halecium 10, sracilis, Lovenella 1

10, 14, 47, 86 disticha 12, 18, --25-26, 32, 81, 86, 88

elatlnosa 10, 15, 48, --60-61, 65, 86 rica, Clytia 10, 15, 48, 49, -50, 86 hemis~haericum.Phialidiurn 50

Hydractinia 32, 33 Stylactis 78 horii, Ostroumovia 22 9, 18, -24, 88

agassizi 9, 12, 17, 28-29, 78, 86, 88 Liriope 76 -- catharinensis 75 conirostris 75 scutigera 75, 80 11, 19, 75-76, 80, 88 7-

0, 6, 53, 54, 57-58, 86 longissima, Obelia 10, 15, -5% , Clytia 51 64 a 63, 64 gracilis 10, 16, 19, 61-65, 86, 88 loveni, Gonothyraea 10, 1574q 59-60, 65, 81, 86 lyons i, 12, 17, 20-2T X, 88 maculat v- Maeotias inexpectata 11, 19, --74- 75, 88 maeotica, Odessia 22 nsis, Blackfordia 67 elomaris 10, 13, 41-42, 18, -34,'8- minuta, 34 -mlra, ~utirna 11; 19, 69-70, 88 -mlrabilis, Syncoryne 28, 78, 79 22

d d lyonsi 9, 12, 17, --20-23, 86, 88 pallasi 22 multicilia, Bougainvillia 38 multitentaculata, Bousainvillia 38

, .. nutricula, ~urritopsis9, 12, 17, --30-31, 77, 78, 86, 88 60 Obelia 48, 60, 61 icuspidata 10, 15, --53-54, 57, 58, 78, 86 comrnissuralis 10, 15, 54-55, 86 15; 55; 86 -- , 15,95-57, 79, 81, 86 a 10, 16,-53y54, 57- 58, 86 longissima 10, 15, 58, 86 -7 spp. 9, 19, --58-59, octonaria Cunina. 11, 17, 31, -77, 88 Cunocantha 77 octopunctata, Rathkea 9, 18, --34-35, 88 maeotica 22 Opercularella 69 lacerata 66 0, 16, 65-66 86 - -9 scidactyla 10, 12, 18, --44-45, 86, 88 0stroumovia 22

L parvum, Dipleuron 6 3, sis, Clytia 10, Pennaria tiarella 25,

Periaonimus- - 44 -I apicatus 44 serpens 44

um carolinae 10, 19, -66, 88 Plumular ia 78, 79 a 78 plumulif era, Thuiaria 78

carnea 78 -mlnlma 9, 18, -34, 88 minuta 34 portmannl,P Staurocladia 84 ac

78 ruaosa.J Boucrainvillea 36 rugosa, 9, 13, 17, 27, --36-39, 49, 55, 59, 65, 71, 79, 86, 88 Sarsia 29 eximia 28 sa 9, 12, 17, 27-28, 78, 86, 88 Schizotricha tenella 11, x,73,- -75, 86, 87 scutigera, Liriope 75, 80 serpens, Perigonimus 44 Sertularia 60, 72 argentea 11, 16, 45, 46, 48, 49, 50, 51, 59, 60, 62, 65, 66, 71-72, 78, 86

stookeyi 78, 79 simplex, Antennularia 78 s tookevi , Sertularia 78, 79

L strangulata, Dipurena 9, 12, 17, --26-27, 86, 88 Stylactis 32 arge 31 hooDeri 78 syncoryne mirabilis 28, 78, 79 Sytlactis arqe 31 tenella, ~chizotricha11, 16, -73, -75, 86, 87 tenuis . Cam~anulina69 tetraphylla; Liriope 11, 19, --75- 76, 80, 88

argentea 71, 78, 79 argentia 71 cupressina 78, 79 plumulif era 78 tiarella, Pennaria 2 5, 79 Tiaricodon 22 Tubularia 23 crocea 9, 13, 24-25? 78, 81, 86 9,T2T17, --27-28, 78, 86, a 40, 41 Turritopsis nutricula 9, 12, 17, --30-31, 77 ulvae, Clytia 53 10, 19, -61, 88 7 9, 11, 19, -67, 88 Zanclea costata 9,- 12, 18, --29-30, 86, 88 gemrnosa 2'3

PLATES PLATE 1

Moerisia lyonsi. dumortieri crocea . Halocordyle disticha .

PLATE 2

Turritopsis nutricula. Hydractinia arge. Hydractinia echina ta . rugosa . Garveia cerulea , f emal.e . Garveia f ranciscana , f ema le Garveia f ranciscana , Kiale . Aselomaris michaeli . Amphinema dinema.

PLATE 3

Proboscidactyla ornata Eudendrium album. Eudendrium ramosum. Halecium Clytia c edwardsi. johns toni . kinca idi. Clytia paulensis. Obelia bicuspids ta .

PLATE 4

Obelia commissuralis. Obelia dichotoma .

PLATE 5

PLATE 6

Moerisia lvonsi. Ectopleura dumortieri. Hybocodon prolif er . Halocordvle distichs. Dipurena Linvillea Sarsia tubulosa . Zanclea costa ta (After Mayer, nutricula .

PLATE 7

Ra thkea Bougainvillia carolinensis. Bouaainvillia ruaosa 4 -. Nemopsis bachei.

Obelia SD . iuvenile .

PLATE 8

Eucheilota ventricularis. Lovenella gracilis, 2 days old. ,s old.

medusa. Eutima mira, Liriope tetraphylla . digitale, specimen in poor condition. Cunina octonaria .