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Notice: © 1981 California Malacozoological Society. This manuscript is an author version with the final publication available and may be cited as: Mikkelsen, P. S. (1981). A comparison of two Florida populations of the Coquina clam, variablis Say, 1822 (: ). I. Intertidal density, distribution and migration. The Veliger, 23(3), 230-239.

•U/--< I

THE VELIGER

A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. BerlceJey, California

VOLUME 23 JANUARY J, J98I NUMBER 3

CONTENTS

Evolution and Function of Asymmetry in the Archaeogastropod Radula. (2 Plates) CAROLE S. HICKMAN 189 Reproductive Biology of Three of Abalones (Haliotis) in Southern California. (3 Plates; 7 Text figures)

THEODORE TUTSCHULTE & JOSEPH H. CONNELL 195 Studies on the Formation of the Crossed Lamellar Structure in the Shell of Strombus gigas. (2 Plates)

HIROSHI NAKAHARA, MITSUO KAKEI & GERRlT BEVELANDER .• 207 Male Characteristics in Female N assarius obsoletus: Variations Related to Locality, Season and Year. (2 Text figures) BLAKEMAN S. SMITH 2 I 2 Rectification of the Generic Placement of Sclerodoris tanya (Marcus, 197I), comb. nov., A from Southern California, with a Range Extension to the Gulf of California, Mexico. (I Plate; I Text figure) HANS BERTSCH 2J7 Growth and Production in Exploited and Unexploited Populations of a Rocky Shore Gastropod, Turbo sarmaticus. ( 10 Text figures)

A. McLACHLAN & H. W LOMBARD. 22J Reprint ~ A Comparison of Two Florida Populations of the Coquina Clam, Say, J822 (Bivalvia: Donacidae). 1. Intertidal Density, Distribution, and Migration. (8 Text figures) PAUL STEPHEN MIKKELSEN • • 230

[Continued on Inside Front Cover]

Distributed free to Members of the California Malacozoological Society, Inc. Subscriptions, by Volume only, payable in advance to Calif. Malacozool. Soc., Inc. Volume 24: $37.50 plus mailing charges $1.50 U. S. A; $5.- for all foreign addresses Single copies this issue $J6.-. Postage extra. Send subscription orders to California Malacozoological Society, Inc. J584 Milvia Street, Berkeley, CA 94709, U. S. A Address all other correspondence to Dr. R. STOHLER, Editor, Depatment of Zoology University of California, Berkeley, California 94720, U. S. A. CONTENTS - Continued

New Distributional Records for Two California Nudibranchs. WILLIAM B. JAECKLE •••••• . . . . . 24° A Cephalic Dimple in the Terrestrial Snail Achatina achatina. (2 Plates)

RONALD CHASE & MICHELE PlaTTE ••••••• . • • . . 241 Siphonal Eyes of Giant Clams (Bivalvia: Tridacnidae) and their Relationship to Adjacent Zooxanthellae. (2 Plates; I Text figure) PETER VFANKBONER ...... 245 The Effect of Pinnotheres hickmani on the Meat Yield (Condition) of Mytilus edulis Measured Several Ways. (2 Text figures) C. L. PREGENZER. •. ..•.•••••••••• 25° Size Gradients and Shell Polymorphism in Limpets with Consideration of the Role of Predation. (9 Text figures) B. HARTWICK .. ..•. 254 Physiological Effects of Desiccation and Hypoxia on the Intertidal Limpets Colli- sella digitalis and Collisella pelta. (7 Text figures) BRUCE LEON BOESE & AUSTIN W. PRITCHARD Behavior of the Gastropod columbiana (Prosobranchia: ). BRETTON W. KENT .•... 275 A Niche Analysis of Coexisting Thais lapillus and Urosalpinx cinerea Populations. DAVID A. JILLSON NOTES & NEWS ... BOOKS, PERIODICALS & PAMPHLETS

Note: The various taxa above species are indicated by the use of different type styles as shown by the following examples, and by increasing indentation. ORDER, Suborder, DIVISION, Subdivision, SECTION, SUPERFAMILY, FAMILY, Subfamily, , (Subgenw) New Taxa Page 230 THE VELIGER Vol. 23; NO.3

A Comparison ofTwo Florida Populations

of the Coquina Clam, Donax variabilis Say, 1822

(Bivalvia : Donacidae)

1. Intertidal Density, Distribution and Migration I

BY

PAUL STEPHEN MIKKELSEN

Harbor Branch Foundation, Inc.; RR I, Box 196; Fort Pierce, Florida 33450

(8 Text figures)

INTRODUCTION posed sandy beaches on the central eastern (Indialantic Beach; 28°5.]'N Lat.,80033.4'W Long.) and southwest­ Donax variabilis Say, THE COQUINA CLAM, lives in the surf ern (Sanibel Island; 26°25.3'N Lat.,82°4.8'W Long.) zone on sandy exposed beaches of the eastern United States coasts of Florida (Figure 1). The transect method of sam­ and the northern Gulf of Mexico. The nomenclature of pling was used (Figure 2.) An initial sample was collected this species was, until recently, in a state of confusion. at the point of maximum wave recession at the time of MORRISON (1970, 1971) pointed out that the correct name sampling. Additional samples were taken at I m intervals for the species is Donax protracta Conrad, 1849. However, along transect A, normal to the beach face, to the point of the name Donax variabilis Say, 1822 was proposed for con­ maximum wave advancement at the time of sampling. servation (Boss, 1970) and subsequently accepted by the The latter point was nearest the backshore and became I.C.Z.N. (MELVILLE, 1976). saturated only temporarily by the swash of the waves. Donax uariabilis occupies the intertidal zone from the Transects B, C, and D were at 25 m intervals. Transects high (EDGREN, 1959) to low tide mark (PEARSE, et al., E, F, G, and H were 5 m apart. The closer-spaced transects 1942). Densities are variable, to a maximum of about were selected to eliminate the possibility of missing local­ 156oojm' (EDGREN, op. cit.). Many authors (ALDRICH, ized aggregations by using too large a sampling interval. 1959; LOESCH, 1957; PEARSE, et al., 1942; TIFFANY, The number of cores taken per monthly sample varied due 1971; TURNER & BELDING, 1957) have noted intertidal to changing width of the swash zone, with a monthly aver­ migrations of D. uariabilis. TIFFANY (op. cit.) and TURNER age of 40 cores at Sanibel Island and 49 at Indialantic & BELDING (op. cit.) have stated that this migratory behav­ Beach. ior is stimulated by the acoustic shock of breaking waves. At Indialantic Beach, collections were taken about 3 Contrarily, only once (EDGREN, op. cit.) has D. uariabilis hours after low tide, on the rising lowest tide of the month, been reported as nonmigratory. I report here a second case and precisely at low tide on the lowest ebb tide of the pre­ of a nonmigratory population, even greater densities, and ceding weekend at Sanibel Island, except the first collec­ possible explanations for the intertidal distribution of two tion (April, 1976) which was made midway between a low populations of D. oariabilis. and a high tide. This change in timing at Sanibel Island was made after having observed the nonmigratory behav­ MATERIALS AND METHODS ior of the Donax on that beach. Specimen samples were collected,using a 15.0 em diam­ Coquinas were collected once each month, from April eter (0.018m') polyvinyl chloride (PVC) corer, to a depth through September, 1976, from the intertidal zone of ex- of IO cm. Because the clams are restricted to the upper­ most 4cm of sand (EDGREN, 1959), the core contained all • Contribution number 187 of the Harbor Branch Foundation, Inc. living specimens. Samples were sieved, using a 1.2 mm Vol. 23; NO·3 THE VELIGER Page 231 mesh. Sand samples were taken in an identical fashion, and salinity was taken by refractometer to the nearest immediately adjacent to the specimen cores, but with a 0.5%0. Beach profiles were measured by triangulation 5.0 ern diameter corer and to a depth of 4 ern. Standard (KING, 1972) at I m intervals from the seaward limit of granulometric sieve analyses (INMAN, 1952) were con­ dune vegetation to the base of the surf zone at the time of ducted on each sample. sampling. Wave height of 10 consecutive waves at their Surf zone water temperature was measured to +- 0.5 0 C, breaking point was measured using a graduated staff.

A B o 2, kilometers

26° t------f-..IIIiI::-:-L-r---f----++-H

a 50 100

0 25 kilometers .'

80'

West Longitude West Longitude

West Longitude

Figure I

Location of sample sites (*): (A) General location; (B) India­ lantic Beach and (C) Sanibel Island Page 232 THE VELIGER Vol. 23; NO·3 t ...... SEA ~ Transect: A BCD EFGH o .. Line of Maximum Wave Recession

, ~ . ~ ., <:: ~ , 0 ~ . N · ..<:: ~ ~ ~ . ·

Figure 2

Diagrammatic representation of the sampling grid

RESULTS The mean particle size (Dse) of the sand was 0'58mm (coarse sand; WENTWORTH, 1922) on Indialantic Beach and 0.26 mm (medium sand) on Sanibel Island. Mean par­ Beach slope exhibited a mean drop of about 5.2 crnzrn ticle size at Indialantic generally decreased progressing up (a slope of 3.0°) at Sanibel Island and 12.0 cm/m (a slope­ the beach face, while at Sanibel the mean particle size re­ of 6.9°) at Indialantic Beach. The beach at Sanibel ap­ mained relatively constant (Figure 4a). Both beaches had peared to be slightly more stable than Indialantic Beach, a uniform sand (uniformity coefficient = D,o/Dlo< 5) based on comparison of slope variation (Figure 3). Mean with Sanibel Island being comparatively less uniform than wave height was 23 em at Sanibel and 91 cm (4 x greater) Indialantic Beach (D6o/DlO = 3.14 and 2.61, respectively). at Indialantic. Irregular semidiurnal tides at Sanibel The less uniform sand at Sanibel Island was due to the ranged about 0.8m, while at Indialantic Beach the tides presence of an abundance of variably-sized large shell frag­ were regular semidiurnal and averaged 1.2 m (Doty, 1957; ments. Mean particle size and uniformity coefficients were U.S. Coast and Geodetic Survey, 1975), or 1.5 x greater nearly constant between transects, although some varia­ than the range for Sanibel Island. Surf zone temperature tion in the uniformity coefficient was evident at Sanibel and salinity ranges were 21.0-27.5 °C and 3°.0-35.0%0 at (Figures 4b, 5b). This slight variation was probably due Sanibel Island, while at Indialantic Beach the ranges were to the sorting and subsequent deposition of large shell frag­ 23·0-27·5°C and 30.0-36.0%0' ments by waves, and beach scalloping. Vol. 23; NO·3 THE VELIGER Page 233

o

...... -.\...... " SANIBEL \. -. ' .... , "...... ISLAND '., -...... , -'-, " ...... , . '-, -. -...... • ••••-. e. "'. ... ' ...... - ......

INDIALANTIC BEACH

3 ----______MayApril (no Sanibel data) ...... June -'-'-'- July August September 4

o 10 20 4° Beach Width (m)

Figure 3

Beach profiles

A total of 28832 specimens of Donax uariabilis were lantie Beach Donax were more dispersed in the wider surf collected from Sanibel Island, and 477 from Indialantic zone, the ratio of the density per square meter of Sanibel Beach. The ratio of Sanibel to Indialantic Donax per to Indialantic Donax was, on the average, 80: I (Table I). linear meter of beach was 60: I (Table I). At either loca­ These ratios are based on a monthly average of 3337'2 tion, there was little difference in numbers collected per individuals at Sanibel and 552 at Indialantic per linear transect between those at 25 m intervals and those 5 ill meter of beach, and mean densities of 7 14I/m" at Sanibel apart. However, because the Sanibel Island clams were and 88/m2 at Indialantic (Table I). However, common concentrated in the lower intertidal levels and the India- densities at Sanibel frequently reached 20 ooo/rn" and Page 234 THE VELIGER Vol. 23; NO·3

Table I

Density and numbers.

L Sanibel ISland~ Indialantic Beach

N/m' o~ area ",m~kd ~/lineal~_,~,~bea(h I Transe~t~ Transects

Sanibel Indialantic Sanibel Indialanti¥A-U E-H I Total # cores A-D E-H Total # cores - I

April 72 1') 342 200 42 7 49 18 I 12 17 29 41 May 103% 'Hi I 11i11t1 (i72 I 3',fJ! 1678 5239 28 4:, 54 97 56

June 2654 llili 116919 1051' I 1220 1216 2436 51 I 41 III 152 51 July 11114 124 62292 714 I 4[79 4791 8970 38 :17 61i 101 46

August 5424 41) 12:,44 143 II, 1711\ 2948 4686 48 20 29 49 56 Sept. 11189 :,4 :,1749 124 . 40tH 1171 7452 37 31 16 47 48

Total 14821 14011 28832 240 184 293 477 298 Mean 7141 1'8 11:172 552 2470 2335 4805 40.0 I 31 49 80 49.7 1 1715 Std. Dev. ',210 :,() I 22,,1i:1 121 .1 J 708 3249 8.3 12 36 46 Coeff. of 7:1% ,,7% (i8% :,8% 69% 71% 68% 20.8% '19% 7'1% 58%

variation II _l ====~'====~======

once reached 600oo/m2 in a small localized area during sites (Mikkelsen, unpublished data), the large difference September. At Indialantic in June and July, densities were in the population of Donax uariabilis may be attributed to commonly 1 50o/m", with a maximum of 2 soo/m" for a the physical differences in the habitats, e.g., the beach pro­ localized area during July. Intertidal distribution and den­ files, wave energy, and sand grain size. The clams' "pref­ sity was patchy at both beaches, but Donax seemed to erencc" for a shallower sloped beach can be supported in "prefer" the shallower beach slope, finer sand, and lower part by EDGREN'S (1959) observations on Clearwater wave energy of Sanibel Island. Beach, Florida ".... that conditions near the pier, which The Indialantic population was always near the center resulted from or were reflected in the shallower slope of of the swash zone (Figure 6). The clams were active, and the beach, were somewhat more favorable for Donax than made frequent migrations up and down the beach face, they were further north," where the beach "became pro­ assisted by the wash of the surf. Although at each low tide gressively steeper." It was presumably the wave moderat­ the Indialantic Donax were washed into the subtidal re­ ing action of a nearby pier which decreased the wave gion (personal observation), they regained their intertidal height on this section of beach, producing a shallow beach position with the subsequent incoming tide. At Sanibel, the Donax were nonmigratory and existed in high concentra­ tions in the lower fifth of the intertidal zone, in a band about 4-5m in width (Figure 6a) and could be found at this position at any stage of the tide. There was little varia­ tion in the distribution of Donax down the length of the Explanation of Figures 4 and 5 on the following page beaches (Figure 6b).

Figure 4­

DISCUSSION Variation of mean sand particle size with (A) core level and (B) transect (-- Sanibel; --- Indialantic) Population Density Figure 5

Because no difference was noted in the abundance of Variation of uniformity coefficient with (A) core level and predators or in environmental parameters between sample (B) transect (-- Sanibel; --- Indialantic) Vol. 23; NO·3 THE VELIGER Page 235

A B April April 1.0 1.0 / ------" --- 0·5 ------'"" o o May May 1.0 l.0 ------vs) ------~, - 0 ...... , June E june ------E l.0 ------~ 0·5 ------U3 0 v july July ~ 0·5 1------p:; 0 - August August J:: 1.0 '" ------~ 0·5 1------o September September l.0 l.0 ~--- (l·5 ------~ ------o - o Mean l.0 Mean l.0 0·5 1------~ ------f-- o o o -1 6 A B c o E F G H Core Level (m) up the Beach Face Transect

Figure 4

A ,,-- , , B ------2 ------"" -- ..... ------April --- April o o

I <, I ; ) M:1Y -1 ~ 2 ------o - 0 c - june ::; (.) ------june ------~ 2 ~ 2 v o 0 8 0 o - ~ _ ...... ~ .':' ------Jul; .§ 2 ------july <£ 0 ·2 ------:::> 2 ------August August-- o o <, 4 4 ~- 2 September o __rv!/ o ----:-- ""-- i--"'" ------~ ------Mean o o

o 2 3 4 5 6 A B c DE F G H Cnre Level (m) up the Beach Face 'Iranscct: Figure 5 Page 236 THE VELIGER Vol. 23; NO·3

A n 80 80 60 April 60 April 0 4 40 20 20 ------o -- - - - May 0 \--- May 4 20 .... ------..... , _ 20 "­ .... -::-. ------<: 0 <: -- ...... 0 --- .9 --- .Q --- ;;; 20 June ;;; June :; '- :; 20 - - --- 0. 0 ---"" 0, 0 ------c, ~ 0 -- 20 '- July...... 0 '0 20 - - E 0 - ---/ E 0 ---- ~'" August '"~ August ~ 20 ~ 20 - ---...... - ..... 0 -- /- o 40 September 20 20 - 0 ------o - - 20 ------.... Mean Mean ----~------~------20 ------",,--..:: 0 o - - 0 2 3 4 5 6 7 A B C DE F H Core Level (01) up the Beach Face Transect

Figure 6

Location of the population of Donax oariebilis as it varied with (A) core level and (B) transect (-- Sanibel; --- Indialantic)

slope which Edgren described as "somewhat more favor­ profile occurred, indicating the deposition of both sand able for Donax." The lower intertidal levels at Sanibel and Donax into the intertidal region, probably from were often very crowded with individuals. These extremely subtidal areas. The small yield of specimens from the first high densities may be the result of the nonmigratory be­ collection in April at Sanibel was not because the spcci­ havior in the presence of wave action, resulting in the mens were washed offshore, but rather because the collec­ subsequent deposition and accumulation of at the tion was taken midway between a low and high tide. lower intertidalleveI. Because of this sampling strategy, it appears that the pop­ The size of the Donax populations also appeared to ulation which had remained in the lower intertidal region fluctuate with the change in beach profile. For example, and did not migrate up the beach face with the incoming the deerease in the intertidal population at Sanibel in June tide was almost completely missed. Salinity changes (Fig­ (Table I) may have been caused by the same conditions ure 8) during the sampling months did not appear to have which removed a large amount of sand from the beach influenced fluctuations in the size of the populations. (Figure 7). As a consequence, a portion of the population The dense, larger population of Donax variabilis at may have been washed into the subtidal region, thus be­ Sanibel Island may be considered resurgent, that is, peri­ coming unable to readily regain its intertidal position by odically but irregularly experiencing nearly complete ex­ the time of sampling. Similarly, at Sanibel in July, an in­ terminations, especially during warm months, followed by crease in both population size and area under the beach re-establishment of the population in subsequent years Vol. 23; NO·3 THE VELlGER Page 237

130 rr------...... 5 3(jn:~------.... ." ~ u ~ 120 35 4 "0 U •~IIQ s~ Q) :::s 100 .... -_ ...--- ... - .....--- ..:--... -- I ~ 80 -- _...... --- --...... --- -- o o bi) o 70 '1====:r:====I::===:::J====:t====f1 0 ....:l April June July August September April July August September

Figure 8

Number of Donax uariabilis collected per month, and area under Monthly variation in surf zone salinity the beach profiles (-- Sanibel; - - .- Indialantic) (-- Sanibel; --- Indialantic)

{communication with Sanibel residents and personal ob­ infestation by parasites (PELSENEER, 1928; CaE, 1956), servation}. However, massive exterminations do not seem and various environmental and biological factors (Jail N­ to occur at Indialantic Beach in populations of either SON, 1968). Thus, both biological and environmental fac­ Donax variabilis or the sympatric D. parvula Philippi, tors may contribute to rapid population declines in the 1849. The cause of the Sanibel Island Donax population genus Donax and probably for D. uariabilis. exterminations remains unknown. A possible explanation was provided by GUNTER (1947) who attributed massive Migratory Behavior and Intertidal Distribution oyster catastrophes in the Gulf of Mexico to high tempera­ tures combined with excessive salinity. However, it is pos­ Many authors (ALDRICH, 1959; ANSELL & TREVALLION, sible that he found only the indirect cause for such dcplc­ 1969; EDGREN, 1959; JACOBSON, 1955; JOHNSON, 1966a, tions. These temperature and salinity conditions could I966b; MORI, 1938, 1950; POHLO, 1967; STOLL, 1937, have facilitated an infestation of the clams by the parasite 1938; TiFfANY, 1971; TRUEMAN, 1971; TURNER &. BELD­ Dermocystidium marinum. Mackin, Owen, and Collier, ING, 1957; WADE, 1964, 1965, 1967a, 1967b; IRWIN, 1950, which is known to severely deplete populations of 1973) have reported on the intertidal migrations of Donax the oyster, Crassostrea virginica (Gmelin, 1791), in the spp. and speculated on or tested the stimulus for migra­ Gulf of Mexico (MACKIN, 1951) and the Chesapeake Bay tion. In addition to D. variabilis, other species of Donax (see JOYCE, 1972). Although this aspect was not investi­ noted to be nonmigratory are D. gouldii (sec HEDGPETH, gated, Dermocystidium marinum or other parasites may 1957; POHLO, op, cit.), D. [aba Gmelin, 1791, and D. infest Donax and affect the population size. uittatus DaCosta, 1778 (see ANSELL & TREVALLlON, op. CaE (1957) stated that resurgent populations of Donax eit.). In considering the many reports involving intertidal have been noticed on both coasts of the United States, but did not mention the species involved. Such resurgences migrations, it is unfortunate that only a few (EDCREN, op. have been noticed for Dall, 192 I (CaE, cit.; JOHNSON, 1966a; TURNER & BELDING, op, cit.; WADE, 1953,1955,1956; JOHNSON, 1966b, 1968), Donax uittaius 19673) have noted such parameters as beach slope, wave DaCosta, 1778 (PELSENEER, 1928), and Donax "tumida" impact, and sand particle size in an attempt to correlate Philippi, 1849 (= Donax texasiana Philippi, 1847) these factors with migrations. TIFFANY (op. cit.) and TUR­ (LoESCH, 1957). Extensive, rapid depletions in the size NER & BELDING (op. cit.) experimentally determined that of D. gouldii populations have been attributed to such the migratory behavior of D. variabilis was controlled by causes as exposure to freshwater emanating from a hot the acoustic shock/stimulation of the breaking waves on spring area and high temperatures (JOHNSON, 1966b), the beach. THE VELIGER Vol. 23; NO·3

EDGREN'S (1959) observations on Clearwater Beach central eastern (Indialantic) and southwestern (Sanibel and my own on Sanibel Island (both on the west coast of Island) coasts of peninsular Florida. Sanibel Island sup­ Florida) showed Donax variabilis to be nonmigratory. ported a population of D. variabilis 60 times greater in However, Edgren observed that the Donax maintained a size and 80 times as dense as that of Indialantic Beach, position near the high tide mark while my observations probably due to lower beach slope and wave energy at showed the species to maintain a very low intertidal posi­ Sanibel. Intertidal migrations occurred constantly at tion. Although the wave size at Sanibel (a low energy Indialantic Beach, with the Donax maintaining a position beach) may be small, the population surely experienced about the center of the swash zone. Sanibel Island Donax some degree of acoustic wave shock, and yet the clams were nonmigratory and lived predominantly at low inter­ were not stimulated to migrate. Nonmigratory behavior tidal levels. This unusual nonmigratory behavior is thought of both the Clearwater Beach and Sanibel Island Donax to be a local adaptation to cope with the combination of populations may also be influenced by beach slope. How­ low beach slope and wave energy in conjunction with ever, it is difficult to compare Sanibel's slope of 3.00 with irregular semidiurnal tides and low sand permeability. Edgren's non-quantitative "quite gentle slope." On Tur­ Therefore, the magnitude and degree of beach slope, tidal ner Beach, Captiva Island, about IS km northwest of the regime, wave energy, and sand particle size and penne­ Sanibel sample site, where the beach slope, wave impact, ability necessary for intertidal migrations of D. variabilis and sand grain size are greater, Donax variabilis is migra­ remain uncertain. tory. The nonmigratory behavior of the Sanibel Island Donax could thus be a result of, or the lack of one or a combination of these factors. The combination of small ACKNOWLEDGMENTS waves and low beach slope causes large areas of the beach to be exposed with a small drop in the tide, thereby inhib­ I am particularly indebted to Drs. Robert H. Gore and iting the ability of Donax to follow the tide. If regular Robert W. Virnstein, whose help was a major asset in the migrations did occur at Sanibel, the individuals could preparation of this paper. My gratitude is also due to easily become stranded above the swash zone for long Drs. Kerry B. Clark and James A. Lasater for their con­ periods of time due to the irregular semidiurnal tide. By tributions. I also thank Sally Hatton, Debbie' Wells, Ed­ maintaining a low intertidal position, the Sanibel DOI~ax ward Kobovitz, and Alan Siegel for their enthusiastic avoided this. assistance with the sampling, and especially Paula Mikkel­ In addition to beach profiles, tidal regime, and wave sen for her help with the collecting and sorting of the energy, sand particle size and permeability may affect specimens and preparation of the original thesis manu­ Donax intertidal migrations and distribution. At India­ script. This work comprises a portion of a master's thesis lantic, Donax had no apparent difficulty in burying in the at Florida Institute of Technology, Melbourne, Florida. coarse sand. At Sanibel, many clams did not, or probably could not bury themselves completely, and once dislodged were washed about on the surface of the sands throughout Literature Cited several consecutive wave periods before partially resecur­ ing themselves in the sand. The Sanibel sand is of medium ALDRICH, J. W. 1959. Activities of coquina clams. Atlant. Nat. -4 (I): 41 -43 grain size and is finn when wet. This sand has a perme­ ANSELL, ALAN DAVID .t. ANN TREVALUON 1969. Behavioral adaptations of intertidal mollusks from a tropical ability (see KRUMBEIN & MONK, 1942) an order of m:lg­ sandy beach. Journ. Exp. Mar. Biol. Ecol. 4 (I): 9 - 35; 14 text figss. nitude lower than Indialantic Beach sand, and is not Boss, KENNETH J. appreciably loosened by wave wash. The movement of 1970. Donax uariabilis Say, 1822 (; Bivalvia); proposed vali- dation under the plenary powers. Z. N. (5.) t923. Bull. Zool. the clams by waves had a tendency to concentrate and Nom. 27: 2°5' 206 COE, \VESLEY ROSWELL deposit the individuals in the lower intertidal zone (Figure 1953. Resurgent populations of littoral marine invertebrates and their 6a). This concentration and deposition was similar to that dependance on ocean currents and tidal currents. Ecology 34 (I) : 225- 229; I text fig. of the larger sand and shell fragments (Figures 4<:1, sa). 1955. Ecology of the bean clam, Donax gould; [sic], on the coast of southern California. Ecology 36 (3): 512 - 514; 2 text figs. 1956. Fluctuations in populations of littoral marine invertebrates. Journ. Mar. Res. 15 (3): 212 - 232; 9 text figs. SUMMARY 1957. Fluctuations in littoral populations. In: Joel W. Hedg- peth (ed.) , Treatise on marine ecology and paleoecology. vol. .. Eco­ logy. Mem. 67, Geol. Soc. Amer.: 935' 939; 2 text figs. Donax variabilis Say, 1822 was collected monthly [rom CO:'iRAD, TIMOTHY ABBOTT 1849. Descriptions of new fossil and Recent shells of the United late spring to early fall of 1976 from two locations on the States. Journ. Acad. Nat. Sci. Phila. (2) I: 207 - 209 Vol. 23; NO·3 THE VELJGER Page 239

DACOSTA, EMANUEL MENDY.S MELVILLE, R. v: 1778. Historia naturalis testaceorum Brittaniee, or the British concho- 197 6. Opinion 1057. Donas oariabilis Schumacher, 1817 (Mollusca: logy. London, 254 pp.; '7 pits. Bivalvia) suppressed under the! plenary powers ; type species designated DALL, WILLIAM HEALEY for Latona Schumacher, 1817· Bull. Zoo!' Nom. S3(1)' '9 - 21 192 r. Summary of the marine shell bearing mollusks of the northwest MORI} SYUlTI coast of America. from San Diego) California, to the Polar Sea, mostly 1938. Donax semigranonu Dunker and the experimental analysis of its contained in the collection of the United States National Museum. behavior at flood tide. Zoo!' Mag. Tokyo (- Dobutsugoku Zasski} with illustrations of hitherto unfigured species. U. S. Nat. Mus. 50 (I): 1-12 Bull. 112: '-217; 22 pits. (24 February Ig21) 1950'. Characteristic tidal rhythmic migration of a mussel, Donax DOTV, MAXWEl.L STANFORD umlgranosus Dunker, and the experimental analysis of its behavior. 1957. Rocky intertidal surfaces. In: Joel W Hedgpeth (ed.), Zoo1. Mag. Tokyo (- Dobutsugoku Zasski) 59 (.. 1: 87 - 89 Treatise on marine ecology and paleoecology. vol. I. Ecology. Mem. 67. MORklSON, JOSEPH PAUL ELDRED Geo!' Soc. Amer.: 535 - 585; 18 text figs. '970. East Florida Donax. Seafari .. (7): 1 - 2; 3 tat figs. EDGREN, RICHARD A. 197 1. Western Atlantic Donax. Proc. Bio1. Soc. Wash. 83 (48) , r 959. Coquinas [Donax variabiliJ) on a Florida beach. Ecology 545 - 568; 2 pIts. 40 (1): 498 - 502; 3 text figs. PEARSE, A. 5., HAROLD J. HUM" " G. W. WHARTON GMELIN. JOHANN FRIEDJUCH 1791. Caroli a Linne systema naturae per regna tria naturae. Edirio 1942. Ecology of sand beaches at Beaufort, North Carolina. Eco!' Monogr. 12 (,): 136 - 190 decima tertia. Lipsiae (Leipzig), Germany, I (6): d. 6 PELSENEER, R. . GUNTER, GORDON J 947. Catastrophism in the sea and its paleontological significance. 19.8. Les parasites de! mollusques et Ies mollusques parasites. Bull. with special reference to the Gulf of Mexico. Amer. journ. Sci. Soc. Zoo!. France 53: 158 - ,8g 2i5: 669 - 676 PHILIPPl, RUDOLPH AMANDUS HEDGPETH, JOEL WALKER ,847· Testaceorurn novorum centuria. Zeitschr. f. Malakozool. 4: 1957. Sandy beachr-s In: Joel W Hedgpeth (cd.), Treatise on 71 - 77 marine ecology and paleoecology. vol. 1. Ecology. Mem. 67, Geol. Soc. 1849. Centuria altere restaceorum novorum (contin.}. Zeitschr. f. MalakozooL 5 (10): 145 - 150 Amer.: 5B7 M 608; J 1 te-xt figs. INMAN, D. L. POHLO, Ross H. r952. Measures for describing the size distribution of sediments. 1967. Aspects of the biology of Donax gouldi [sic] and a note ,qn Journ. Sed. Petro!' 22 (3): 125 - 145 evolution in TelIinacea (Bivalvia). The Veliger 9 (3): 330 - 337; IRW1N, THOMAS H. 5 tat figs. (I January 1967) r973. The intertidal behavior of the bean clam, Donax gouldii DaU, SAY, THOMAS 1921. The Veliger 15(3): 206-212; 2 pits.; 3 text fig" (I Jan. '73) J822. An account of some of the marine shells of the United States. JACOBSON, MORRIS KARLMANN Journ. Acad. Nat. Sci. Phila. 2: 302 - 325 1955. Observations on Donax [OHOT at Rockaway Beach, New STOLL, EVA York. The Nautilus 68 (3): 71- 77 (II February '955) 1937· Beobachtungen Iiber die Fortbewegung bei einigen grabenden JOHNSON, PHYLLIS T. Muscheln. Rev. Suisse Z001. 44: 383 1966a. On Donax and other sandy beach inhabitants. The Veliger ! 938. Sur la mode de locomotion de quelques mollusques marins. 9 (1): '9 - 30 (I July Ig66) Trav. Stat. BioI. Roscoff 16: 3 - 33 1966b. Mass mortality in a bivalve mollusk. Limnol. Oceanogr. II TIFFANY, WILLIAM J., III (3)' 429 - 431; , text fig. 197 r, The tidal migration of Donas oariabilis Say (Mollusca: Bival- 1968. Population crashes in the bean clam, Donax gouldi [sic], and via). The Veliger Ii (I): 8.-85; 2 text figs. (I July 1971) their significance to the study of mass morta.liby in other marine iOM TRUEMAN, E. R. vertebrates. j ourn. Invert. Pathol. 12: 3494358; I text fig. 197 J. The control of burrowing and the migratory behavior of Donax JOYCE, EDWIN A. denticulatus (Bivalvia: Tellinacea). journ. Zoo!' 165 (.. ): 453 - 469; 1972. A partial bibliography of oysters. with annotations. Florida 9 text figs. Dept. Nat. Res. spec. pub!. no. 34, 84 6 pp. TURNER. HARRY JACKSON, Jr... Davrn L. BEl.DING KING, C. A. M. 1957. The tidal migrations of Donax uariobilis Say. Limno1. 1972. Beaches and coasts. 2nd ed., New York, 51. Martin's Press Oceanogr. 2 (2): 120 - 1.4 57 0 pp. UNlTED STATES COAST AND GEODETIC SURVEY KRUMBEIN, \V, C .• G. D. MONK 1975. High and low water predictions; East coast of North and South 1942. Permeability as a function of the size parameters of unconsoli- America. Washington, U. S. Govt. Print. Off.; 290 pp. dated sand. Arner. lnst. Mining Metallurg. Engrs. Tech. Publ. No. W AVE, BARRY A. '''92, Petro!' Tech, pp. 1 - II 1964. Not ... on the ecology of Donax denticulatus (Linne). Proc. LOESCH, HAROLD CARL Gulf Carib. Fish. Inst. (17 th Ann. Sess.) : 36 - 41 1957. Studies (In the ecology of two species of Donax on Mustang 1965. Studies on the biology of the beach clam, Donax (Bivalvia: Island, Texas. Publ. Jnst. Mar. Sci" Uriiv. Texas 4: 201· '227; 19 Donacidae) in the West Indies. Ph. D. thesis, Univ. West Indies, text figs. Jamaica; 271 pp.; 55 figs. MACKIN, J. G. 19673. Studies on the biology of the West Indian beach clam Donax 1951. Histopathology of infection of Crassostrea virginica (Gmelin) denticulonu Linne. I. Ecology. Bull. Mar. Sci. '7 (I): '49- 174; by Dermocystidiurn marinum Mackin, Owen, and Collier. Bull. 7 text figs. Mar. Sci. Gulf. Carib. I (I): 72 - 87 Ig67b. On the , morphology, and ecology of the beach clam, MACKIN, J. G., H. M. OWEN. A. COLLIE.R Donax striatus Linne. Bull. Mar. Sci. '7 (3): 723 - 740; 5 text figs. 1950. Preliminary note on the occurrence of a new protistan pares!te, WENTWORTH, C. K. Derrnocys1idium marinum n. sp. in CraHostrea virginica (Gmelin}. t 922. A scale of grade and class terms for clastic sediments. j ourn, Science III (2883)' 3.8 - 329 Geol. 30(5): 377-39' THE VELIGER is open to orig-inal papers pertaining- 1O any problem concerned with mollusks. This is meant to make facilities available for publication of orig-inal articles from a wide rleld of endeavor. Papers dealing with anatomical, cytological, distributional, ecolog-ical, histological, morphological, phys­ iological, taxonomic, erc.; aspects of marine, freshwater or terrestrial mollusks from any region, will be considered. Even topics only indi­ rectly concerned with mollusks may he acceptable. In the unlikely event that space considerations make lirnitatinns necessary, papers dealing with mollusks hom the Pacific reg-ioll will he g-iven priority. However, in this case the term "Pacific reg-ion" is to be most liberally interpreted. It is the editorial policy to preserve the individualistic writing style of the author; therefore any editorial changes in a manuscript will be sub­ mitted to the author for his approval, before going- to press. Short articles containing descriptions of new species or lesser taxa will be given preferential treatment in the speed of publication provided that arrangements have been made by the author for depositing the holotype with a recognized public Museum. Museum numbers of the type specimens must be included in the manuscript. Type localities must be defined as accurately as possible, with geographical longitudes and latitudes added. Short original papers, not exceeding 500 words, will be published in the column "NOTES & NEWS"; in this column will also appear notices of meetings of the American Malacological Union, as well as news items which are deemed of interest to OUI' subscribers in general. Articles on "METHODS & TECHNIQUES" will be considered for publication in another column, provided that the information is complete and tech­ niques and methods are capable of duplication by anyone carefully fol­ lowing the description given. Such articles should be mainly original and deal with collecting, preparing, maintaining, studying, photo. graphing, etc., of mollusks or other invertebrates. A third column, en­ titled "INFORMATION DESK," will contain articles dealing with any problem pertaining to collecting, idcntif yirrg, etc., in short, problems encountered by our readers. In contrast to other contributions, articles in this column do not necessarily contain new and original materials. Questions to the editor, which can be answered in this column, are in­ vited. The column "BOOKS, PERIODICALS, PAMPHLETS" will attempt to bring reviews of new publications 10 the attention of our readers. Also, new timely articles may be listed by title only, if this is deemed expedient. Manuscripts should be typed in final form on a high grade white paper, 8\12" by I I", double spaced and accompanied by a carbon copy. A pamphlet with detailed suggestions for preparing manuscripts intended for publication in THE VELIGER is available to authors upon request. A self-addressed envelope, sufficiently large to accom­ modate the pamphlet (which measures 5y:!" by 8Y:!"), with double first class postage, should be sent with the request to the Editor. EDITORIAL BOARD

DR. DONALD P ARnOTT, Professor of Biology DR. JOHN MCGOWAN, Associate Projessor of Hopkins Marine Station of Stanford University Oceanography

DR. WARREN O. AnDIcoTT, Research Geologist, U. S. Scripps Institution of Oceanography, La Jolla Universitv of California at San Diego Geological Survey, Menlo Park, California, and Consulting Associate Professor of Paleontology, Stan­ DR. FRANK A. PITELKA, Professor 0/ Zoology ford University University of California, Berkeley, California

DR. JERPV DnNCIHUE, Professor of Chemistry DR. ROBERT ROBERTSON, Pilsbry Chair of Malacology University of Pennsylvania, Philadelphia, and Department of Malacology Research Associate in the Allan Hancock Foundation Academy of Natural Sciences of Philadelphia University of Southern California, Los Angeles DR. PETER U. RODDA, DR. J. WYATT DURHAM, Professor of Paleontology Chairman and Curator, Department of Geology University of California, Berkeley, California California Academy of Sciences, San Francisco DR. CADET HAND, Professor of Zoology and Director, Bodega Marine Laboratory DR. JUDITH TERRY SMITH, Visiting Scholar Department of Geology, Stanford University University of California, Berkeley, California Stanford, California DR. JOEL W HEDGPFTH, Adjunct Professor Pacific 11:1 rine Station, U niversi ty of the Pacific DR. RALPH I. SMITH, Professor of Zoology Dillon Beach, Marin County, California University of California, Berkeley, California

DR. A MYRA KEEN, Professor of Paleontology and DR. CHARLES R. STASEK, Curator of Malacology, Emeritus Bodega Bay Institute Stanford University, Stanford, California Bodega Bay, California DR. VICTOR LOOSANOFl', Professor of Marine Biology DR. T. E. THOMPSON, Reader in Zoology Pacific Marine Station of the University of the Pacific University of Bristol, England

EDITOR-IN-CHIEF ASSOCIATE EDITOR

DR. RUDOLF STOHLER, Research Zoologist, Emeritus MRS. JEAN M. CATE University of California, Berkeley, California Rancho Santa Fe, California