JOURNAL OF TEE ROYAL MICROSCOPICAL SOCIETY. FEBRUARY 1886.

TRANSACTIONS OF THE SOCIETY.

I.-Frmhwa&w Alga (including Ch/orophyllmeous Protophyta) of tb English ; with descriptiom of twelve mw species. By ALFRED W. BENNETT,F.R.N.S., F.L.S., Lecturer on Botany at St. Thomas's Hospital. (Read 13th January, 1886.) PLATESI. AXD II. Tm following is a record of the fresh-water organisms observed d&g a six weeks' stay in Aupst and the early part of September 1885, in the district between Windermere and Langdale, West- moreland. As nearly every day's observation added some fresh ies to the list, it is probable that the record is a very incorn- one of the microscopic aquatic flora of this very rich district.

B 2 Transactions of the Society. Nor does it include even all the species actually observed, but onIy such as previous knowledge or the books at command enabled me to identify, or such as I had reason to believe were hitherto un- described forms. In particular the Oscillariaceae and Diatomacee require niuch more careful working out. The Desmiclieae naturally form a considerable portion of the list. During the year 1884 the most important addition to the literature of this interesting class since Ralfs’s ‘ British Des- midiez’ (1848) has been made, in the publication of the Rev. F. Wolle’s ‘ Desmids of the United States.’ Although something has been clone in the interval by Archer, Cooke, Bisset, and others, yet, notwithstanding the great beauty and variety of the form in desmids, and the ease with which a large number of species can be recognized, it is probable that more still remains to be done in this group than in any other of the English flora. It is impossible to praise too highly the beauty and accuracy of the drawings, as a whole, in lialfs’s work. In many instances, however, niy measure- ments ranged somewhat larger than those of the veteran desmidio- logist. With regard to the distribution of desmids, many species seem to be almost ubiquitous, occurring in nearly all gatherings, from all altitudes. Whether other species are, like those of flowering plants, limited in geographical area or in adaptability to climate, is a question which has yet to be answered, and the answering of which mill be by no means easy. I have thought, however, that I have noticed that the larger and more striking species are especially abundant at high altitudes. Gatherings from about 1800 feet, above Codale and Easedale Tarns, were especially rich in these. Unless otherwise stated, all the species named were observed in the district of Loughrigg, Westmoreland. The gatherings were

Fig. 18.--Staurnsti~tm bidlosum Benn. x 400. ,, 19. 11 ,, empty frond x 400. ,, 20. 9) ,, front view x 400. ,, 21. ,, teliferum Ralfs var. conuemm Benn., front view x 400. ,I 22. I, ,, dividing, early stage x 400. 9, 23. ,I 39 ,, later stage x 400. 9, 24. ,, tuberculutum Benn. x 400. ,) 25. ,, enorme Ralfs x 400. ,, 2S.-Tetmcmorus penioides Benn. x 200. ,, 27.-Zypema c)uciutum Cleve, zggosperm germinating while in parent- cell x 200. ,, 28.-Zygnemn H&ulliz Benn., filament in non-conjugating condition x 200. ,, 29. , ,, filament before conjugation x 200. ,, 30. 7% ,, filaments in conjugation x 200. ,, 31.--bfesesocaipus 7 wmanrensis Benn. x 200. ,, 32. 9, ,, with zpgoaperm x 200 ,, ~3.-Gdogonitcm mncrandritm Wittr. x 200. Fresh-watev Qlgx, dc. By A. W. Bennett. 3 made especially from bog and moor pools, met rocks, and the smaller streams. None were taken from the larger streams or lakes.* PROTOPHYTA. PALMELLACEW. Eremosphzra viridis dBy. Glceocystis vesiculosa Nag. ,, rupestris Rabh. Y? botryoides ? Ktz. Schizochlamys gelatinom A. Br. l’almella mucoaa Rtz. Botryococcus Braunii Etz. What may poasibly prove to be a second species of this genus was frequently met with in bog pools. Eaeh colony was about 40 p in diameter, composed aa a rule of thirty-two cells, with no evident investing gelatinous envelope, swimming with considerable velocity and at the same time rotating in the water, without any a areat motive power. The cells themselves were elliptical, and &d with a light green endochrome. Rhaphidium falcatum Cooke (R. polymorphum var. c fa& catum Rabh.). Nephrocytium Agardhianum Nag. 29 Nagelii Griin. Ophiocytium cochleare A. Br. I take this to be identical with 0. m+s Kag.; bnt is the genus rightly placed under vegetable organisms at all ? Scenedesmus acutus Mey. J7 quadricauda Br6b. PROTOCOCCACEB. Protococcus viridis Ag. Chlorococciim gigas Griin. Chlamydococcus pluvialis ? A. Br.

CHROOCOCCAOl3E. Chroococcus turgidus Nag. Wetherlam, Lancasbire. Aphanocapsa virescens Rabh. Forming jelly-like masses on a moist rock along with Nosfoe ItunziftbStbTn. * The names of new species are printed in SMALL cArrTAr.s ; those of spec& new to Britain iti italics. E2 4 Transadions of the Society. Aphanocrtpsa rivularis Rabh. Forming large green shining ,jelly-like masses on grasses hanging over into a spring on Park Fell, Lanwhire, inclosing numerous rhizopcds, diatoms, K.C. Microcystis marginata Eirch. This interesting organism was observed several times in gather- ings from moor pools. The pale blue-green cells were seen to be in constant motion within the hyaline investing membrane. Merismopedia glauca Nag. Wetherlam, . MERISMOPEDIA? PALUDOSA n. sp. Plate I. fig. 1. Each family composed of eight cells, closely packed together without intermediate spaces, and with no evident gelatinous en- velope. Cells square in outline with rounded corners, remarkably regular in form, and each divided into four; cell-contents blue- green. Length of colony, 50 p; breadth, 25 p; cells 12.5 p in length and breadth.* The small number of cells in a colony, and the absence of spaces between the cells, seem su5cient to characterize the species. It was gathered in bog pools, Loughrigg. OSCILLARIICEB. Omillaria violacea Rabh. ,, tenuis Ag. Lyngbya ochracea Thur. ,, innndata Cooke (Phormidium inundatum Ktz.). Ambleside. SIROSIPHONEB. Stigonema saxicolum? Nag. On damp rocks, along with Nostoc humificsum. NOSTOCACEE. Anabaena Hassallii Nords. & Wittr. Cylindrospermum macrospermum Ktz. J> catenaturn Ralfs. Furness Fells, Lanca- shire. Nostoc humifusum Carm. On moist rocks. Nosroc HYALLINUMn. sp. Figs. 2, 3. Free-swimming, very minute. Gelatinous envelope globose or slightly ellipsoidal, 0 - 2 1 mm. in diameter, lamellose, perfectly colourless and transparent. Trichome single in each envelope, * These measurements correspond nearly with those given by Nazeli (‘Gattnngen cinzelhger Algen’) for M. glaucn, but I canuot rt,concile Dr. Choke’s relative meaauremcnta of the different species of Merisinopediu with his plates. hbmovm.&us ellipsoidal or nearly globose, green, 5 p in (&butforty to the length of tho envelope). Eeterocysts bba,very few in number, threc to four in each envelop, @end, green, 6-7 p in diameter. several vimens obtained from a bog pool, . It Borne resamblance to N. mhzutissimacm Ktz., but is much smaller, and the triohomes are much less densely packed in the h dine envelope. According to Kiitzing all the free-swimming ddocs me attached at ht; but this does not seem to be the case with this speciee. ALGB. PEDIABTRE2E. p-nun angdosum Ehrb. ,) Boryanm Turp. ), Ehrenbergii A. Br. P~XAS~UXOOMPAOTUM n. sp. Figs. 4,5. Canobium opal and perfectly regular, 0.09-0'16 mm. in length (or probably more), rather more than half as broad as long. Pkphery oomposed of thirty-two hate cells (in the smaller speci- mene), with two somewhat divergent, very slender tapering, not Wenfate horns, quite as long as the cells themselves. Inrier cells irregalarly polygonal and densely packed, without any laciin~~,in 24 mw~. Ccenobinm invested with a distinct gelatinous en- velop. Endochrome yellom-green ; that of the peripheral cells of s deeper colonr, which gives the appearance, under a low power, of a deep green border. Length of cells ahout 6 p. Bog pools, Loughrigg, not infrequent. The perfectly regular elliptical form, the much yellower endochrome, and the absence of my interstitial spaces between the cells, give this Pedinstrzcuh a Very &tinct appearance from all others with which I am ac- In shape it resembles P. ellipticum Ehrb. (judging LmBslfs$ figme), but differs widely in other respects.

ULOTI~ICBACEIE. B0-k moniliformie Rabh. y9 cakniformk? Eta. ulothrix ZOnaih Ktz. Grisedale, Camberland.

coNFERVAaE2E. GnfaVS fontbalk Be&, 9, tenerrha Ktz. ¶, bombyciria Ag. ~~mpomvulgaris Rabh. 6 Trmwuctions of the 8oclety. CEBTOPHOBACIEZ. Draparnaldia glomerata Ag. Furness Fells, Lancashire. On previous occasions of observing this beautiful plant, I have been struck wit,h the extremely long hyaline seta with which the branches end, many times longer than the green portion of the branch. This is not so figured in this speciea by either Hassall, Kiitzing, or Cooke, though it is in other less common species of the genus. DIATOMAC~. Eunotia Arcus W. Sm. Above Easedale Tam. diodon Ehrb. Cygbella Ehrenbergii Ktz. ,, afiis Rtz. Surirella biseriata BrBb. ,, linearis W. Sm. ,, pinnata W. Sm. Nitzschia sigmoidea W. Sm. Above Easedale Tarn. ,, linearis W. Sm. Amphioxys W. Sm. Na$cula rhomboides Ehrb. ,, rhyncocephala Etz. ,, ovalis W. Sm. ,, amphirhynchus W. Sm. Pinnularia major W. Sm. ,, viridis W. Sm. ,, oblonga W. Sm. ,, lata W. Sm. ,, acuta W. Sm. ,, radiosa W.Sm. ,, gracilis Ehrb. Stauroneis Phmnicentrum Ehrb. 9, gracilk Ehrb. anceps Ehrb. Sp&a pulchella ? Ktz. ,, minutissima Kte. ,, radians W. Sm. ,, Ulna Ehrb. ,, fasciculata Ktz. Gomphonema geminatum Ag. Ambleside. 9, constrictum Ehrb. Do. 9, wuminatum Ehrb. Do. 9, tenellurn W. Sm. Do, Himantidium pectinale Etz. ?f undulatum W. Sm, 9) Arcus W. Sm. Fresh-water Alfi~,&c. By A. W. Bennett. 7 Odontidium hiemale Htz. Ambleside. Fragilaria capucina Desm. Diatoma vulgare Bory. ,, grande W. Sm. elongatum Ag. T’cid’ll e aria flocculosa Ktz. ,, fenestrata Etz. Melosira varians Ag. DESMIDIEB. Hyalotlieca dissiliens Sm. Didymoprium Borreri Ralfs. Desmidinm Swartzii Ag. 9, quadrangulatum Balfs. Frequent in bog pools, Loughrigg, forming, together with HyaZoothaca dissiliens, dense green slimy floating masses. Sphaerozosma vertebratum BrBb. 99 excavatum Ralfs. Micrashrias denticulata Brhb. ,, rotata Gtrev. MIORAB!FERIASOORNUTA n. sp. Fig. 6. Frond oval, very large, 0.355 mm. in length, 0,305 mm. in breadth. The two terminal lobes urn-shaped, very light green, slightly projecting beyond the margin, and quite distinct for their whole length, reaching down to an oval quite colourless piece in the centre ; ends of terminal lobes colourless, concave, not dentate or fimbriate. Each qiiarter with two deep and thee less deep incisions. Margin 27.5 p wide, perfectly colourless, consisting of six distinct pieces, each with a deep indentation. Stream between Codalo and Stickle Tarns, at an clevation of about 1800 feet. Seems quite distinct, not only from its very large size, but in other characters. Diflers from M. der&ieZata in the prominence and distinctness of the terminal lobes; from M. rotata in the terminal lobes and segments of the colourless margin not being bidentate. Nicrasterias fimbriata Ralfs. ,, papillifera BrBb. Y, truncata Coda. ,Y crenats UrQb. Holocystis oscitans Hass. (Micmsterias oscitans Ralfs ; Tetrachastruin inucroimtum and oscituns Dixon ; Micms- terias ~~aucronataauct.). Figs. 7-10. This very polymorpliic species secms to me to have becn well separated by Hassall as the type of a distinct genus ; and, according 8 Transactions of the S&ty. to the laws of priority in nomenclature in use among phanero- gamic botanists, his name excludes Dixon’s Tetrachartrum. The complete absence of radiating lobes and of marginal incisions, as noted by II~assall,separates it well from Micrustmias. The genmal form and the thickness of the frond seems to me indeed to bring it nearer to Ezlastrum, which genus it approaches through E. pectinatma. The most perfectly developed form is that repre- sented in fig. 7, which is not, however, drawn by either Hasmll, Ralfs, or Wolle. The apicd segment is bidentate; the Law1 segment bidentate at the base, and with an additional tooth on the shoulder; but any or all of the teeth may be wanting; and that this does not constitute specific difference is seen by the frequent occurrence of specimens, as shown in fig. 8, in which the two halves exhibit this character in very different degrces. Fig. 9 represents an individual dividing. The cell-wall is finely punctate, as shown iu fig. 10. The size is as variable as the form. In the specimen figured, the length of the frond is 175 p; breadth of basal se,peent, 140 p ; of apical segment, 115 p ; breadth of isthmus, 35 p ; width of neck, 55 p. Both Ralfs’s and Wolle’s measurements are smaller ; but I have seen specimens consideraLly larger. Very comuon in log. pool? In the genus Dolocystis I Ehould include Micrusterias prmattjida Ralfs, &I. liiticeys Nor&., JI. Eitchelii Wolle, and M. disputata Wood (probably uone of these are specifically distinct) ; also Euastrum intsrrnedium Cleve, and var. cuspidcltum Wolle, and E. urwfornie TVulle. Enastnun verrucosnm Ehrb. Yewdale Fells, Lancaahire, and Ambleside. >Y oblongum Grev. Y, muttilobatum Wood (‘Fresh-water Alge of North America,’ p. 135, t. xii. f. 10). Fig. 11. Length of frond, 90 p; breadth, 65 p; breadth of isthmus, 25 p. D8ers from E. oblongum in its smallor size and in the more horizontal direction of the lobes, but agrees in general out- line. The terminal lobe is also quite undivided by any vertical incision. The specimens obRerved by me correspond very closely fo Wood’s description and figure; the species has apparently not been observed before in Europe. Bog pool, Loughrigg. Euastrum crwum Rr6b. ,, pinnatum Rdfi. YY affine Ralfs. Y, ampullaceum Ra&. ,, insigneHass. ,, cunmtum Jen. This seems to me a very well-marked species. Fresh-water Alg~,hc. By A. W. Bennett. 9 Euastrum Didelta Turp. ,, ansatum Ehrb. ,, circulare Ham ,, pectinatum Brhb. ,, gemmatum BiBb. ,, rostratum Ralfs. EUASTBUMORNITHOOEPHALUN n. sp. Fig. 12, Frond minuto, 57 p long, 30 1.1 broad. Each frustule with a basal and central rounded lobe, and a terminal lobe moderately deeply divided vertically, and with a single projecting tooth, the lobe resembling a bird‘s head. Sutural division somewhat shallow. Cell-wall tuberculated. Near to E. vostratuna and to E. pseud- elegans Turn. (Journ. R. Micr. SOC., 1885, p. 935), from the United States, but somewhat larger; the terminal lobe resembling that of E. elegans. Bog pool, Loughrigg. Euastrum elegans Br6b. inerme W. ,, binale Turp. ETJASTBUMLUNDELLII n. sp. (E. biimle y elohaturn Lund., Desm. Suec., p. 23, t. ii. f. 7). Fig. 13. Frond very minute, 28 p long, 14 p broad, truncately elliptical in outline. Frustule three-lobed ; terminal lobe truncate, gibbous, slightly concave, entire, 11 p broad. Sutural constriction deep. Each frustule with a moderately conspicuous projection in the centre. Among Sphagnum, Loughrigg. Agrees in form and size with Lnndell’s variety of E. binale, but seem sdiiciently distinct to merit specific rank. Enwtmm erosnm Lund. ,, insulare Wittr. ,, crenatum Ktz. (Phyc. Germ., p. 135). Fig. 1-1. Frond minute, ahout the size of E. elegans, 45 plong, 30 p broad, hexagonal in outline ; terminal lobe with quite straight ex- tremity and very slight vertical incision, 20 p broad. Each frustule with about three shallow crenations on each side. Suture shallow. Cell-wall not puncta t ed. Bog pool, Loughrigg. This little-known species presents well- marked distinctions from E. ehgans. Although named in Ralfs’s ‘British Desmidiee,’ it does not appear to have been noticed in Britain before. Cosmarium sublobaturn Arch. (Emstrum sublobaturn BrBb). This species seems clearly to have been placed in the wrong genus by Br6bisson and Ralfs. 10 Transactions of the Society. Cosmarium quadratum Ralfs. 7, Cucumis Corda. ,, Ralfsii BrBb. ,, pyramidatum Brkb. ,, crenrttum Ralfs. ,, undulatum Corda. If tetraophthalmum Etz. Above Easedale Tarn. 9, Botrytis Bory.

Y, margaritiferum Turp ,, BrBbissonii Menegh. A good species. ,, speciosum Lund. This beautiful species has already been recorded from Ireland by Archer. ,, amaenum BrBb. ,, ccelatum Ralfs. ,, ornatum Ralfs. ,, cristatum Ralfs. Furness Fells and Wetherlam, Lancashire.

9, Logiense Biss. (Journ. R. Micr. SOC.,1884, p. 191, t. v. fig. 4). ,, turgidum BrBb. ,, Cucurbita BrBb. ,, moniliforme Turp.

9) Wittrockii Lund. (Desm. Suec., p. 31, t. iii. f. 14). Fig. 15. Frond very minute, shape of C. mnrgaritiferacnz, but not crenulated, nearly circular in outline, 25 p long, 22.5 p broad ; the two frustules slightly unequal ; constriction deep ; isthmus 10 p broad. Cell-wall not punctated, perfectly smooth. Frequent in bog pools, Loughrigg; not recorded before in Britain. Certainly a mature form, as it was several times seen in division. Cosmarium oblongurn mihi ( Cosmariunt sp. Reinsch, Cont., p. 82, t. xlii. f. 3). Fig. 16. Frond minute, 55 p long, 22 ,u broad at its broadest part; each frustule elliptical, longer than broad, equally rounded at the base and the apex ; isthmus 11 p broad. Cell-wall not punctated, per- fectly smooth. Bog pools, Loughrigg ; new to Britain. Resembles C. monili- fornte, except that the frustules are elliptical instead of circular. Xanthidium armatum BrBb.

3, aculeatum Ehrb. ,, fasciculatum Ehrb. XANTEIDIUNSPINULOSUM n. sp. Plate 11. fig. 17. Fresh-water Algq &c. By A. W. Bennett. 11 Frond moderately large, the shape of X. fusciculatum; each frustule elliptical or slightly hexagonal, 80 p long by 40 p deep ; isthmus 60 p. Each frustule furnished with four pairs of geminate cmved spines about 25 p long ; the whole of the rest of the edge ciliated with closely set spines or teeth, in one specimen about 12 p long, in another specimen much shorter. Endochrome very grannlar, with a lighter less granular portion in the centre of each frustule. Stream between Codale and Stickle Tarns, at an elevation of abut 1800 feet. Resembles X. fasciculatum in general outline, the length and breadth of the frond being almost exactly the same ; but the constriction between the frustules is much less deep, and the secondary spines seem sufficient to establish it as a distinct species. STAURASTRUMBULLOSUM n. sp. Figs. 18-20. Frond moderately large ; each frustule elliptical, more than twice as long as broad ; 85 p long, 38 p wide, triangular in front view, united by a narrow isthmus 35 p wide. Each frustule with a hemispherical projection which is very conspicuous, especially on front view. Frond and projection uniformly verrucose. Both frond and projection fringed with colourless equidistant unbranched subulate spines. Among moss in stream flowing out of Loughrigg Tarn, and elsewhere, apparently frequent. In outline and the equidistance of the spines, and in the triangular front view, this beautiful species is distinctly a tStaurastrum, but it is double the diameter of S. teliferzcm, which it most nearly resembles. The hemispherical pro- jection on each frwtule, which is remarkably conspicuous, seems to indicate an a5ity with Xanthidium, some species of which it closely resembles in general appearance. Staurastrum dejectum BrBb. Forms a and y. ,, Dickiei Ralfs. ,, muticum BrBb. ,, muricat.um BrBb. ,, hirsutum Ehrb. ,, teliferiim Ralfs fl CONVEXUM n. var. Figs. 21-23. One of the commonest Staurastra in moor pools. I am unable to distinguish it from Rdfs’s species except by the sides being slightly convex, and therefore regard it as a variety of that species, which both Ralfs and Wolle describe as having con- cave sides on front view. The spines are much stouter and less numerous than in S. hirsutum. The process of division of this species is extremely interesting, and presents one of the most rapid 12 Transwtims of thSookety. instances of growth with which I am acquainted. In one example, when first observed (fig. 22) the new pieces were but slightly smaller than the old pieces, only partially filled with endochrome, and the cell-wall perfectly smooth. mihile under observation and drawing they grew to their full size, and became entirely filled with endochrome. The first appearance of spines was now seen ; they rapidly increased in stoutness, and within an hour from the time of first observation the new individuals were perfectly formed. During the whole of this time the individual was in constant motion, but became quiescent as soon as the new formation was completed. The pair remained in contact till the next morning. Staurastrum Pringsheimii Reinsch. >, alternans Br6b. ,, pnnctulatum BrBb. ,, dilatatum Ehrb. ,, polymorphum BrBb. ,, gracile Ralfs. ,, levispinum Bk. (Journ. R.. Micr. Soc., 1884, p. 195, t. v. fig. 5). Y, controversum Br6h. STAURASTBUMTUBTDWULATUM n. sp. Fig. 24. Frond moderately large, 70 p long by 55 p broad ; each frustule nearly hexagonal in shape, 37 p broad at the apex, 30 p at the isthmus; the termiual and upper lateral edges nearly straight or slightly convex ; the lower lateral edges concave. The whole margin, except the lower lateral edges, rough with pearly granules, which are larger at the corners. Surface of frond tuberculated. Bog pool, Loughrigg. Belongs to tbe ‘Rection with conmve sides ; near to S. finitidurn Arch. and S. Sebaldi Reinsch. Staurastrum ? enorme Ralfs. Fig. 25. This rare and remarkable desmid was gathered in a bog pool an Park Fell. Although, as described by Ralfs, it is by far the least symmetrical apecies of the genus, the bilateral symmetry is never- theless seen in certain positions. The frnstules are tuberculated, and from each tubercle springs a cluster of hyaline spines with a common barn. Some writers give this aa a synonym of Polyedrizcm . elzorrne dBy., but probably in error, as 8 figure in Cooke’s ‘British Fresh-water Alga ’ certainly does not represent this plant. Arthrodeamus convergens Ehrb. 3, Incus Br6b. Cylindrocystis diplospora Lund. (Desm. Suec., p. 83, t. v. fig. 7.) Frequent. Probably frequently overlooked from its resemblance to the bicellular condition of 8 Maocarpus, but easily distinguished &e&-watev A2gtq &e. By A. W. Bennett. 13 by ita smctller size, and the very light green endochrome, with a distinct vesicle in the centre of each semi-cell or frustule. Tetmemorus Brebissonii Menegh.

Zygosperm large, orbicular, olive-brown, about 1* 66 times diameter of frond, not inclosed in a membrane, resembling there- fore that of l! granulatus rather than of T. lmk Tetmemorus laevis Etz. ,, granulatus Bre'b. TETUEMORUSPENIOIDES n. sp. Fig. 26. Frond about the size of T. granulatus, 190 p long, by 47 -5 p broad, linear-elliptic, distinctly notched at each extremity, but without any lip-like process. Margin continuous, with scarcely any constriction. Cell-wall not punctated or granulated. Among Sphagnum, Furness Fells, Lancashire, apparently frequent. This species appears to form a connecting link between the genera Tetmemorus and Penium. The absence of a central constriction is characteristic of the latter genus, while the terminal notch seems to bring it under the former. Peninm margaritaceum Ehrb., vars. a and 'y Ralfs. ,) cylindrus Ehrb. ,, polymorphum Perty. ,, lagenaroides Roy. (Journ. R. Nicr. Soc., lSM, p. 197, t. v. fig. 6). ,, cucurbitinum Bisa (1. c. p. 197, t. v. fig. 7). ,, digitus Ehrb. ,) internipturn BrBb. Park Fell. ,, closterioides hlfs. ,, truncatnm BrBb. ,, Brebissonii Ralfs. Docidium noctnlosum BrBb. Ambleside. ,, trnncatum Br6b. ,, clavatum Ktz. ,, baculum Brhb. Spirotaenia condensata Br6b. obscura Ralfs. Furneas Fells. ClosCrium ~un~la~iill. ,, acerosum Schrank. ,, turgidum Ehrb. Park Fell. ,, Ehrenbergii Menegh. ,, Dians Ehrb.

9, didymotocum Corda var. p Ralfs. ,, costatum Corda. ,, striolatum Ehrb. 14 Transactions of the Society. Closterium intermedium Ralfs. ,, juncidum Ralfs. ,, corm Ehrb. ,, acutum BrBb. ZYGNENACELE. Zygnema cruciatum Cleve. Fig. 27. This is much the commonest species of the order in the mom- tain streams. It was rarely seen in conjugation ; and in lateral conjugation not at all. Measurements showed in some instances the female cells distinctly larger than the male cells ; in others there was no appreciable difference. In several instances one male filament was seen in conjugation with two female filaments, never the reverse. In one instance a zygosperm was seen germinating while still inclosed in the parent filament ; and then, in harmony with observations previously made on Spi9*ogyra,+the direction of the germinating filament was at right angles to the axis of the parent-cell. This was the more remarkable, as the zygosperm is in this species quite spherical. Zygnema Hassallii mihi (Tyndaridea anomala Hass. ; Zygitema anomalum Cooke, not Ktz.). Figs. 28-30. Cells 52 p in length, 28 p in breadth ; zygosperm perfectly spherical, 20 * 5 p in diameter, olive-green to emerald-green. This species is common in roadside runnels, and presents several dis- tinctive characters from others of the genus. In the non-con- jugating and most frequent condition (fig. 28), the cells are almost entirely filled up by a dark-green endochrome; it is only when about to coqjugate (fig. 29) that it becomes differentiated into two stars ; and then not 50 distinctly as in 2. er~ia~~~.The mucous sheath by which the filaments are invested is distinctly visible at all stages. Conjugation seems to take place only when the fila- ments are nearly dried up, and has apparently only been observed in this country by Hassall, Ralfs, and Jenner. I can entirely confirm the etatement of these observers that the zygosperms are formed in one of the conjugating filaments (fig. 30) ; Kutzing’s species, in which they are formed In a canal between the filaments, must, therefore, be a different one. I think, however, Hassall is in error in figuring the zygosperms as formed indifferently in either filament ; this is quite contrary to numerous observations of my own. Spirogyra porticalis Vauch. ,, longata Vauch. ,, tenuissima Ham.

* Journ. Linii. SOC.(Bot.) xx. (1664)’~.430. Fresh-water Algs, &c. By A. W. Bennett. 15 MESOCARPEE. Mesocarpus scalaris dBy. MESOCARPUS(3) NEAUXENSIF~n. sp. Figs. 31, 32. Sterile cells 125 p long by 20 to 25 p broad. Endochrome in a single axile plate, with one row of large starch-corpuscles, and numerous smaller ones. Conjugation lateral, between two adjacent cells. Fertile cells somewhat ventricose, 200 p long by 50 p broad at the widest part, connected with the adjoining empty cell by an elbow 50 p broad, across which the dividing septum reaches only about half-way. Zygosperm oval, 90 p by 40 p, always nearer to the end of the cell where conjugation has taken place ; call-wall of zygosperm quite smooth. Gathered in a duck-pond, Neaum Crag, Bridge. I am doubtful about placing this interesting species under Mesocarpus. It agrees with that genus altogether in general appearance and in the arrangement of the endochrome; but I am quite unable to detect the extra membrane to the zygosperm on which de Bary md Wittrock rely to establish the essential difference in the process of ‘(spore-formation ” in the Mesocarpea? and Zygnemeae ; and wherever lateral conjugation has been observed in Mesocarpus (by de Bary), the zygosperm is formed not in one of the two cells, but in the connecting canal between them. In some respects, especially the ventricose appearance of the fertile cells, it approaches Wittrock‘s genus Gonatonerna. If placed in Mesocarpus, M. neaumensis differs from all the other species with emooth membrane to the eygosperm, in the form of the cells, and in the size and form of the eygosperm, as weU as in the mode of conjugation. Staurospermum gracillimum Ktz. SIPHONEZ. Vaucheris sessilis Vauch. Ambleside. ,, terrestris Lyngb. Pool in slate quarry, Yewdale Fells, Lancashire.

~DOGONIACEB. (Edogonium vernale ? Wittr. Furness Fells. ,, macrandrum Wittr. Fig. 33. Oogonia pear-shaped, three together, 40 p in length. Dwarf male as long as length of oogonium, two-celled, attached to the eentre oogonium. Furness Fells. adogonium acrosporum ? dBy. Furness Fells. Bulbochaete setigera Ag. ,, pygmaa Wittr.