' ^ u / HARVARD UNIVERSITY 1 R LIBRARY OF THE Museum of Comparative Zoology /y*->WU/*a,,s-J VOLUME 3 1955-1956 AUG 2 C 1956 TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and deals with an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. MEMBERS OF THE EDITORIAL COMMITTEES FOR PAPERS PUBLISHED IN THIS VOLUME Reeve M. Bailey, University of Michigan Frank A. Brown, Jr., Northwestern University Theodore H. Bullock, University of California David Causey, University of Arkansas Fenner A. Chace, Jr., United States National Museum Albert Collier, United States Fish and Wildlife Service Frank B. Cross, University of Kansas Norman Hartweg, University of Michigan Horton H. Hobbs, Jr., University of Virginia Lipke B. Holthuis, Rijksmuseum van Natuurlijke Historie, The Netherlands Carl L. Hubbs, Scripps Institution of Oceanography Clark Hubb, University of Texas L. H. Kleinholz, Reed College Ernest A. Lachner, United States National Museum Victor L. Loosanoff, United States Fish and Wildlife Service George A. Moore, Oklahoma Agriculture and Mechanical College Walter G Moore, Loyola University Thurlow C. Nelson, Rutgers University Robert W. Pennak, University of Colorado Edward C. Raney, Cornell University Luis Rene Rivas, University of Miami Donald C. Scott, University of Georgia Hobart M. Smith, University of Illinois Robert E. Snodgrass, United States Department of Agriculture Hermann Weber, Universitat Tubingen, Germany John H. Welsh, Harvard University Austin B. Williams, University of North Carolina Ernest E. Williams, Harvard University Paul A. Wright, University of Michigan CONTENTS OF VOLUME o NUMBER PAGE 1. NOTROPIS ASPERIFRONS, A NEW CYPRINID FISH FROM THE MOBILE BAY DRAINAGE OF ALABAMA AND GEORGIA, WITH STUDIES OF RELATED SPE- CIES Royal D. Suttkus and Edward C. Raney 1 2. A NEW LOUISIANA COPEPOD RELATED TO DIAPT- OMUS (AGLAODIAPTOMUS) CLAVIPES SCHACHT ( COPEPODA, CALANOIDA) Mildren Stratton Wilson 35 3. A NEW SPECIES OF STERNOTHERUS WITH A DIS- CUSSION OF THE STERNOTHERUS CARINATUS COM- PLEX (CHELONIA, KINOSTERNIDAE) Donald W. Tinkle and Robert G. Webb 51 4. A NEW CAMBARUS OF THE DIOGENES SECTION FROM NORTH LOUISIANA (DECAPODA, ASTACIDAE) George Henry Penn 71 5. NOTROPIS EURYZONUS, A NEW CYRINID FISH FROM THE CHATTAHOOCHEE RIVER SYSTEM OF GEORGIA AND ALABAMA Royal D. Suttkus 83 6. FACTORS INFLUENCING THE RATE OF OXYGEN CONSUMPTION OF THE DWARF CRAWFISH, CAM- BARELLUS SHUFELDTII (DECAPODA, ASTACIDAE) Milton Fingerman 101 7. IDENTIFICATION AND GEOGRAPHICAL VARIATION OF THE CYPRINODONT FISHES FUNDULUS OLIVA- CEUS (STORER) AND FUNDULUS NOTATUS (RA- FINESQUE) Jerram L. Brown 117 8. THE PHYSIOLOGY OF THE MELANOPHORES OF THE ISOPOD IDOTHEA EXOTICA Milton Fingerman 137 9. OSMOTIC BEHAVIOR AND BLEEDING OF THE OYS- TER CRASSOSTREA VIRGINICA Milton Fingerman and Laurence D. Fairbanks 149 10. ANATOMY OF THE EYESTALK OF THE WHITE SHRIMP, PENAEUS SETIFERUS (LINN. 1758) Joseph H. Young 169 Printed in the U.S.A. at Neiv Orleans, by Hauser Printing Co.. Inc. - Nrt * iN LesN Oiecmsj •ff^aAsis sir® ©as ast g®@iL@(a^r Volume 3, Number 1 July 8, 1955 C*TA* "A- '<>■/***$ J N0TR0P1S ASPERIFRONS, A NEW CYPRINID FISH FROM THE MOBILE BAY DRAINAGE OF ALABAMA AND GEORGIA, WITH STUDIES OF RELATED SPECIES ROYAL D. SUTTKUS, DEPARTMENT OF ZOOLOGY, TULANE UNIVERSITY, NEW ORLEANS, LOUISIANA and EDWARD C. RANEY, DEPARTMENT OF CONSERVATION, CORNELL UNIVERSITY, ITHACA, NEW YORK MUS. COMP. ZQOL ^ UBRARY Jill 1QKCT HARVARD UNIVERSITY TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the area bordering the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and deals with an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Carl L. Hubbs, Professor of Biology, Scripps Institution of Oceanography, La Jolla, California. Reeve M. Bailey, Curator of Fishes, Museum of Zoology, Uni- versity of Michigan, Ann Arbor, Michigan. Ernest A. Lachner, Associate Curator of Fishes, United States National Museum, Washington, D. C. Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers may be purchased by individuals, but subscriptions are not accepted. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers to the editor. Re- mittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zool. Price for this number: $0.50. George Henry Penn, Editor, Meade Natural History Library, Tulane University, New Orleans, U. S. A. Assistants to the Editor: Carol L. Freret Donald W. Tinkle N0TR0P1S ASPER1FR0NS, A NEW CYPRINID F THE MOBILE BAY DRAINAGE OF ALABAMA AND GEORGIA, WITH STUDIES OF RELATED SPECIES ROYAL D. SUTTKUS,i Department of Zoology, Tulane University, New Orleans, Louisiana and EDWARD C. RANEY,2 Department of Conservation, Cornell University, Ithaca, New York Nine small species of Notropis which possess 2, 4 — 4, 2 teeth, 7 or 8 anal rays, a dark lateral band on the side of the body (bypsilepis excepted) and, for most, a prominent basicaudal spot, are found in the eastern Gulf of Mexico drainages from the Apalachicola Bay drain- age of Florida and Georgia to the Mobile Bay drainage of Alabama and Mississippi. Although most are common forms and some are used as bait fishes, their systematic status has been confused. Char- acters which differentiate the lowland forms, N. roseus and N. peter- soni, and N. chalybaeus, and a definition of N. xaenocephalus, have recently been given by Bailey, Winn and Smith (1954). Two other forms, N. baileyi and N. bypsilepis, have been described and their relationships with N. lutipinnis and N. chrosomus elucidated by Suttkus and Raney (1955 a and b). This study describes a new species, gives comparative data for Notropis xaenocephalus, roseus, petersoni, and to a lesser extent for chalybaeus, and offers a key for the identification of the forms mentioned above. Robert H. Gibbs and Philip P. Caswell, Cornell students, collected many of the types and comparative material housed in the Cornell University fish collection. Many of the specimens from the Black Warrior River system were obtained through Ralph L. Chermock, University of Alabama, and were collected by Bancroft Cooper, Her- bert D. Gibson, G. Hollis, T. Taylor, and Barry D. Valentine. Charles D. Hancock assisted the senior author in obtaining the specimens collected in Wilcox County, Alabama, now housed at Tulane Univer- sity. Helen J. Illick has made available the counts for the cephalic lateral line pores from her unpublished studies. Ernest A. Lachner of the U. S. National Museum, assisted us during our examination of type specimens and critically reviewed the manuscript, as did Reeve M. Bailey and Carl L. Hubbs. We are deeply indebted to all of the above for their assistance. Counts and measurements were taken as detailed in Hubbs and Lagler (1947: 8-15). 1 Aid for collecting material was obtained from the Tulane Uni- versity Council on Research. 2 Aid for ichthyological field work was obtained from the Cornell University Faculty Research Grants Committee. 4 Tulane Studies in Zoology Vol. 3 NOTROPIS ASPERIFRONS, sp. nov. Figs. 1 and 2, Map 1 Notropis xaenocephalus. — Gilbert, 1891: 154 and 157 (a complex of N. roseus, North R., Tuscaloosa, Ala. and N. asperifrons, Mulberry Fork, Blount Springs and Eight Mile Cr., Cullman, Ala.). The type material consists of 91 specimens, 28 to 60 mm in stand- ard length, which were seined from 12 localities in the Alabama River system. Additional material examined includes 69 specimens, 22-55 mm in standard length, taken from nine localities in the Black War- rior River system. Below, in parentheses, are indicated the numbers of specimens followed by the range of standard lengths in milli- meters. In addition to standard abbreviations for states and compass directions, with the following "of" deleted, these abbreviations are used: Co. = County, Cr. = Creek, Hwy. = Highway, mi. r= mile or miles, R. = River, trib. = tributary ( of ) , coll. = collected, CU. = Cornell University fish collection, TU = Tulane University fish col- lection, USNM = United States National Museum. Material. — Holotype, CU 28262, an adult female 50 mm in stand- ard length, captured in the Alabama R. system in Holly Cr. at Ram- hurst, 8 mi. N. Murray Co. line on U. S. Hwy. 411, Murray Co., Georgia, on June 12, 1952, by Robert H. Gibbs and Philip P. Cas- well. Seven paratypes, CU 28263 (35-52), bear the same data as the holotype. Other paratypes, listed below, are from the Mobile Bay drainage. Alabama: CU 28261 (1, 40), trib. Terrapin Cr., approximately 4 mi. N.E. Piedmont on Ala. Hwy. 74 at the Cherokee-Calhoun county line, June 14, 1952; CU 28260 (3, 38-58), Cheaha Cr., trib. Choo- colocco R., 3.3 mi. S.W. Munford on U. S. Hwy. 21, Talladega Co., June 14, 1952; TU 4251 (28, 31-42), trib. Waxahatchee Cr., a trib. Coosa R., 4.7 mi. S.W. Columbiana on Ala. Hwy. 25, Shelby Co., June 15, 1952, and Wilcox Co., June 3, 1951: TU 3426 (8, 30-35), Pursley Cr., trib. Alabama R., 3.4 mi. S.W. Camden on Ala. Hwy. 11; TU 2974 (22, 28-36), Gravel Cr., trib. Pursley Cr., 6.3 mi. S. Camden on Hwy. 11; TU 3063 (5, 37-41), trib. Pursley Cr., 1.8 mi. E. Camden on Ala. Hwy. 10; UMMZ 111122 (2, 37-39), between Waverly and Opelika or between Waverly and Lafayette, September 13, 1930; UMMZ 111125 (7, 25-51), Sougahatchee Cr. (Loachapoka Cr.), October 24, 1930; UMMZ 162594 (2, 49-60), Sougahatchee Cr., 4 mi. N. Auburn, Lee Co., October 9, 1940. Georgia: USNM 164968 (1, 45.5) and 164969 (1, 47.9), Etowah R. (probably trib.), Rome by D. S. Jordan; UMMZ 139104 (3, 44-51), trib. Conasauga R, 7.3 mi. S. Dalton, U S. Hwy. 41, Whitfield Co., August 7, 1936. Other material examined from the Black Warrior River system, Tuscaloosa Co., Alabama is as follows: CU 19268 (2, 42-44), lower Cottondale Cr. near Hurricane Cr., approximately 2 mi. N. Cotton- dale, October 9, 1950; CU 28259 (10, 25-43), trib. North R, 1 mi. S.E. Sterling and 5 mi. S.E. New Lexington, June 23, 1951; CU 28258 (9, 30-41), Puro Cr., trib. North R., 4 mi. E. New Lexington, June No. 1 Suttkus and Raney: A New Cyprinid 5 23, 1951; CU 28257 (6, 35-44), Blue Cr, trib. Black Warrior R, 25 mi. N.E. Tuscaloosa on Ala. Hwy. 63, March 3, 1951 and from the same locality, CU 28256 (16, 22-44), March 9, 1951; USNM 43474 (8, 33-42), Mulberry R, Blount Springs, coll. by P. H. Kirsch in 1889; USNM 36672 (11, 32-38), Eight Mile Cr., Cullman, coll. by Gilbert and Swain in 1884; UMMZ 88852 (6, 42-55), Blount Springs Cr, Blount Co, September 19, 1929; UMMZ 158285 (1, 39), trib. Locust Fork (flowing W.), 3 mi. N.N.E. Oneonta, Hwy. 32, Blount Co, September 5, 1939. Diagnosis. — A small species of Notropis with 2, 4 — 4, 2 teeth and 7 anal rays as the typical counts. Other fin rays are: dorsal 8, pectoral 13 or 14, occasionally 12; pelvic 8, occasionally 9; caudal 19- Lateral line on body complete. Anterior lateral line scales, especially the second and third, elevated. Scale counts ( typical ) : predorsal rows 14 or 15; above lateral line to dorsal origin 5; below lateral line to anal origin 3 or 4; in lateral line 36, occasionally 37; around body before dorsal fin 19 to 21; around caudal peduncle 12. Body elon- gate, wide and slightly compressed. Dorsal and ventral body contours only slightly elevated; caudal peduncle elongate. Head subtriangular as viewed from above and laterally; snout blunt. Mouth inferior. Jaw moderately inclined, rising anteriorly to the lower level of pupil. Dorsal origin slightly behind pelvic origin. Strong but narrow dark lateral band, not reduced on snout; dark chevrons present above and below the anterior lateral line pores. Prominent basicaudal spot con- tinuous with and wider than lateral band on caudal peduncle. Tem- poral canal outlined by dark line. Mid-dorsal streak before dorsal fin obsolescent; streak behind dorsal lacking or developed only under the posterior base of the dorsal fin. Fins all relatively small. Size small, to 60 mm standard length. Allied to Notropis xaenocephalus, hypsi- lepis, roseus and petersoni. Notropis asperifrons is the undescribed form alluded to in the paper by Suttkus and Raney (1955b), under Relationships. Description Some fin and scale counts are included in Table 1 and measure- ments are given in Table 2. The count of the holotype is the modal count for a given character unless italicized in Table 1 or in the Diagnosis. Many characters are also indicated in Figures 1 and 2. Other descriptive data follow. The body is more elongate than in related species; it is relatively wide and rather sharply compressed. The dorsum is only slightly elevated; the contour is an almost straight line both before and behind the dorsal origin. The ventral contour is only slightly less elevated. The caudal peduncle is long and rela- tively thin. The anterior lateral line scales, especially scales two and three, are somewhat more elevated than the others in the lateral line or else- where. In this character it is more extreme than hypsilepis. When viewed laterally the head is a rather sharp triangle although the tip of the snout is bluntly rounded. The mouth is inferior; the Tulane Studies in Zoology Vol. 3 w H E-t w CO £ a o a >* H O W pq < Eh ~ 2 a O o u « ft. 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CQ CD +-> in CO s ►J Tf CO CM •«* H OS 00 CO CD CM CO ft K co <» eo S co ©■ .<=> ft cj CJ © A ft » CO Si CO © © ^ e h v. © CO to S 5- cd «a e3 CD c3 O i— i 01 CQ o m a u 0) «4H 3 CJ cS 01 cS .-1 0) > o -r 93 CM — GO lO -h 00 OJ 3S 00 CM I 05 t)< I cd oo m Ifl »1 W H rl oo m cd I i-i CM CM CD H H CO CO 'Cf 00 CD 00 CO CM 1-H H IN H CD w _cy 'o 01 CO s ft <» CJ © s © co eo 5> cj ft ft <» CO "« Si CO © © "» ^g S H 5~ ft No. 1 Suttkus and Raney: A New Cyprinid 7 tip of the snout overhangs the upper lip and the lower lip is included within the upper lip. The mouth is moderately oblique; the gape rises anteriorly to the lower level of the pupil. The posterior tip of the lower jaw just reaches a vertical line projected from the front of the eye. The length of the eye is slightly less than the snout. All fins are relatively short (Table 2). In the erect position, the posterior border of the dorsal and anal fins is almost straight; when depressed the tip of the first ray greatly exceeds that of the last ray in both. The pharyngeal arch is moderately developed and is less strong than in xaenocephalus* The shelf bearing the lesser row is narrow. The uppermost three teeth in the main row are compressed, pointed and hooked at the tip; the fourth is a cone only slightly curved at the tip. The grinding surface has crenulate edges and is long and well developed on the upper two teeth, is only about half as long in the third, and is practically missing in the lowermost. The two teeth in the lesser row are about half as long as the longest in the major row; each has a well developed grinding surface and a small hook at the tip. The teeth are somewhat more hooked than in xaeno- cephalus. The tooth count in the holotype of asperifrons is 2, 4 — 4, 2 but apparently this character is subject to considerable variation. In para- types from the type locality the counts are 2, 4 — 4, 2 (2); 2, 4—4, 1 (1); 1, 4 — 4, 2 (1); and 1, 4 — 4, 1 (3). In another series from the Alabama R. system the count is 2, 4—4, 2(3). In the Black Warrior R. system variability was noted also although 2, 4 — 4, 2 was counted in nine out of 16 fish; other counts were 2, 4 — 4, 1 (2); 1,4—4,2 (2); 1,4— 4, 1 (1); 1, 3—4, 1 (1); and 2, 4— 3, 1 (1). The reduction in number noted above in the main row is unusual. When reduction occurred in the lesser row no indication of a basal tubercle or socket was discernable and the shelf of the pharyngeal arch often did not seem wide enough to hold another tooth. A sum- mary of the 27 tooth counts follows: 2, 4 — 4, 2 (15); 2, 4 — 4, 1 (3); 1, 4—4, 2 (3); 1, 4—4, 1 (4); 2, 4—3, 2 (1); and 1, 3—4, 1 (1). In five small series of xaenocephahis the teeth were 2, 4 — 4, 2 ( 16) ; 1, 4—4, 2(2); and 1, 4—4, 1(2). A count of 2, 4—4, 2 was found in roseus (4) and in peter soni (6). On the first arch the gill rakers are all small and, including rudi- ments, number 11 or 12. The vertebrae usually number 36 or 37 (Table 3). The nape is fully scaled as is the breast as far forward as a line joining the posterior limit of the pectoral fin bases. The cephalic lateral line canals and pores of five species (asperi- frons, xaenocepbalus, roseus, peter soni and chalybaeus) have been compared. The number of specimens counted is given in parentheses. The anteriormost pore is designated number one. The pore counts 8 Tulane Studies in Zoology Vol. 3 TABLE 2. Measurements of Notropis in Thousandths of Standard Length. For each Character is given the Range of Variation and Below (in Parentheses) the Mean. The Mean Values for asperifrons include the Holotype. xaeno- Species asperifrons cephalus roseus petersoni River System Alabama Alabama Alabama, Ogeechee, Black Warrior, Apalachi- Perdido cola No. and sex Holotype Paratype of spec. 9 6 $.3 $ 5 5.5 $ 5 9-5 $ 5 5,5 $ Standard length 51.6 35-58 45-55 38-51 41-54 Dorsal origin to 504 494-528 490-513 492-509 493-525 snout tip (506) (502) (498) (507) Dorsal origin to 524 491-542 523-539 514-540 496-530 caudal base (521) (531) (529) (519) Dorsal origin to 312 289-320 288-313 284-315 290-314 occiput (305) (300) (302) (303) Pelvic insertion 492 475-506 472-494 472 499 480-512 to snout tip (483) (487) (489) (492) Anal origin to 330 322-351 327-348 328-368 317-349 caudal base (335) (337) (345) (333) Body depth 184 175-197 199-227 201-233 184-234 (187) (209) (220) (211) Body width 136 125-145 121-143 109-146 115-146 (136) (129) (127) (127) Dorsal origin to 113 113-127 126-143 125-153 111-157 lateral line (120) (129) (137) (134) Pelvic insertion 079 072-088 070-090 081-110 083-120 to lateral line (080) (081) (094) (096) Caudal peduncle 233 227-257 206-232 20S-233 222-259 length (242) (219) (221) (233) Caudal peduncle 082 080-091 088-101 092-102 084-097 depth (086) (093) (097) (092) Head length 252 236-254 238-259 220-259 229-268 (245) (248) (247) (256) Head depth 139 136-188 151-164 149-165 150-166 (150) (155) (157) (158) Head width 126 116-132 122-136 122-135 121-136 (124) (128) (129) (131) Interorbital, 082 079-085 077-090 080-092 081-090 least fleshy (081) (083) (086) (088) Snout length 078 073-083 068-083 068-084 077-0S6 (078) (075) (074) (082) Eye length 074 069-077 073-085 068-084 076-086 (072) (078) (076) (081) Upper jaw 074 059-074 073-085 063-077 072-084 length (067) (078) (069) (077) Suborbital least 025 016-027 017-025 021-028 024-032 width (023) (021) (025) (029) Dorsal fin, de- 210 198-223 223-256 226-273 231-258 pressed length (210) (235) (243) (249) Anal fin, de- 143 140-151 177-192 162-197 173-215 pressed length (146) (185) (184) (189) Caudal fin length 235 213-245 238-275 262-277 272-303 from base to tip (236) (258) (269) (284) of longest ray Pectoral fin 178 161-185 186-233 171-200 177-220 length (172) (207) (188) (201) Pelvic fin 153 139-153 142-178 159-186 155-185 length (146) (161) (170) (170) No. 1 Suttkus and Raney: A New Cyprinid 9 are summarized in Table 4 and are not repeated in the description below. The supratemporal canal is always incomplete in the five species. N. asperifrons has two pores on each side (5). N. roseus has two pores on each side (3), or one pore on each side plus a short branch from the junction with the infraorbital with a pore ( 1 ) , or a canal with two pores located more dorsally on each side (1). N. xaeno- cephalus has two pores on each side (6), or two pores on the left and one on the right ( 1 ) . N. petersoni has on the average fewer pores, with one pore on each side (3), or two pores on one side and one on the other (2), or one pore on both sides and a short canal of two pores on the left side ( 1 ) , or two pores on each side ( 1 ) . N. chalybaeus has a higher average pore count and exhibits greater variation than the other species. The supraorbital canal is complete in asperifrons, roseus, xaeno- cephalus, and petersoni, and incomplete in chalybaeus. In asperifrons a vertical projected dorsally from the posterior margin of the eye falls between pores six and seven in those with a count of eight and between seven and eight when the count is nine. N. roseus is es- sentially the same. In xaenocephalus a vertical projected from the posterior margin of the eye falls between pores six and seven (1) or on pore seven (6). In petersoni a projected vertical falls on the next to the last pore (6) and between pores six and seven (1). In chalybaeus the canal is complete with a count of eight (4) and in- complete with a count of nine (2); breaks occur between pores two and three and between five and six. The supraorbital canal ends above the posterior margin of the eye or at a point just posterior of this point; a projected vertical falls between the last two pores. The infraorbital canal of asperifrons is complete in specimens with a pore count of thirteen (2) and fourteen (2); in the specimen with the incomplete canal the pore count is fourteen with a break between pores twelve and thirteen. A vertical projected from the anterior margin of the eye falls between pores four and five (4), and between three and four ( 1 ) . In N. roseus this canal is complete in three specimens which have a pore count of thirteen, fourteen and fifteen. One of the specimens with an incomplete infraorbital canal has a pore count of twelve, with a break between pores three and four, and the other canal has fifteen pores with a break between pores twelve and thirteen. A vertical projected from the anterior margin of the eye falls between pores four and five. In xaeno- cephalus the canal is always complete. A vertical from the anterior margin of the eye falls between pores four and five. In petersoni the canal is complete in six of the seven specimens studied and the pore count is lower than in the four other species compared here. The incomplete canal has a pore count of twelve with a break be- tween pores ten and eleven; a vertical from the anterior margin of the eye falls between pores three and five. In chalybaeus the canal is incomplete in all; a break occurs between pores ten to thirteen. 10 Tulane Studies in Zoology Vol. 3 CO W iJ M •2 © fa o t» w I— t fa Oh o fa w o O CQ fa H 03 O O 0) s £ 03 3 03 00 * O * rH LO 00 l£> i— I i—i m oo 00 i-l io t- ri ^l H OS tJ< i-l iH (N OS 1-1 i-l CO i-H -«3< i-f CO "tf hj nS h & CO 3 W ?DrH CO co Tj 05 S »*^i -£ a, o © 05 | to g © 05 to 00 s to e «© to 05 O co © to 05 ■« c •*a e © to .*» c *■ H *. a. to -c to •3 28 Tulane Studies in Zoology Vol. 3 it has long been speciated and differs in many characters, including a typical anal ray count of eight. The range of the lowland chaly- baeus includes and is greater than that of both roseus and petersoni and the three species have been taken in the same collection on the eastern Gulf lowland where the ranges of roseus and petersoni over- lap. We postulate that cbalybaeus and roseus were evolved from the same stock, and probably they were isolated early; roseus in the Gulf and Mississippi lowlands and cbalybaeus in the Atlantic Coastal Plain area. Subsequently cbalybaeus reinvaded the western lowlands where it is now sympatric with roseus. Apparently N. roseus and Ns petersoni are closely related and the latter probably evolved from a Pleistocene invasion of the Atlantic Coastal Plain by roseus stock. This eastern component {petersoni) evolved to the species level and has reinvaded the Gulf Coastal Plain where it has advanced at least as far as the lower Escambia River. Its subsequent coastwise dispersal to the west and into peninsular Florida, where it is now widely distributed as far southward as the Caloosahatchee River system (Lee Co.) seems to be favored by its tolerance of saline water, a fact recently pointed out by Bailey et al. (1954). The populations of petersoni in peninsular Florida, especially those in the lower west coast drainages, seem to have differentiated and are now characterized by a short (Table 5), slim body, a large eye, bluntish snout, and dark coloration. While N. roseus is primarily a Coastal Plain and lowland species it is presumably physiologically preadapted to permit invasions of upstream habitats. For example it is now known from tributaries of the Black Warrior River, Green and Tuscaloosa counties, Alabama, where it lives sympatrically with asperifrons. While asperifrons, bypsilepis and xaenocephalus probably arose from such invasions by roseus stock, the time and mode of isolation are not clear. The com- mon characters and the range of asperifrons and bypsilepis seem to point to a common ancestry (roseus or roseus-like stock), with sub- sequent differentiation. Besides sharing the basic characters of 2, 4—4, 2 teeth and 7 anal rays the three are similar to roseus in many details of coloration, counts, and proportions as may be seen in the descriptions above and in Tables 1-4. Notwithstanding the close relationships, these forms are differentiated on the species level. N. roseus and asperifrons are sympatric in the Black Warrior and Ala- bama River systems of Alabama; asperifrons was taken with xaeno- cepbalus several times in the Alabama River system; bypsilepis and roseus occur together in a tributary of Lazier Cr., Flint R. drainage, Talbot Co., Georgia. An invasion of roseus in the Flint River section of the Apalachi- cola Bay drainage, which is very close to the extreme of its range, has evolved into a population of roseus which we believe may prove worthy of subspecific recognition. It is not now designated as such since we believe that roseus should be studied throughout its range No. 1 Suttkus and Raney: A New Cyprinid 29 LO W m a. o fa O a — - o fa Cu h > fa o o I— I H O fa o a a o < fa fa a, GO W fa o fa o o — & 03 >-* DS H 1/3 O fa & fa a: 03 c CD ft CO C •h O o -43 U LO OS SO CO I o ■* CO CO LO OS lo io io LO bo -* *tf 13 a -t-> O "* to cs co co o ■■* co co LO CS eg cm o n< CM IM CO CP '3 o CM CD (M CS Tj 00 t- CD i— ( 00 o CM ■^ oo co co tH CM CM 1— 1 tH co 00 CM 00 (MOO !M -C* O CD CO CD to CO '-I H Tt« O t- LO CM co cs t- co cs t> CM CM rH rH 00 CS O rH CM 00 "tf "-l o i-H CM cs cs tH CD CM co CM LO CO CM «-< i— I -* CM CM CM CM CM ~d cS O cs < o — ; ^ p, CO CO *-^ CO s o CO e CO s e <» CS o S Ct) e W Ph CO s eo o CO <» cv> a. MO to C 'S si C e o w ce- rt o CJ CJ re "3 30 Tulane Studies in Zoology Vol. 3 before adding additional names (see Bailey et al., 1954). The trend toward a reduction of tooth number in some samples of asperifrons, a roseus derivative, also occurs in the northern part of the range of roseus. The Flint River population of roseus shows a notable dif- ference in body depth. In fifteen specimens from 43-59 mm in standard length, the body depth expressed in thousandths of standard length ranges from 215 to 286, mean 255; eight females averaged 266 and seven males averaged 243 (see Table 2 for measurements of other samples of roseus). There is also a greater number of cir- cumferential scales, the count usually being 26 in Flint River speci- mens and 24 in those taken in lowland situations. We postulate that xaenocephalus evolved from roseus stock which invaded the Mobile Bay drainage. It now seems to be limited to the Alabama River system while the related asperifrons occurs in both the Alabama and Black Warrior river systems. Many of the salient differences between the two are to be seen in the key, the description given above, in Tables 1-4, and in Figures 1-4. In summary, asperi- frons differs from xaenocephalus in having an inferior mouth; more elevated anterior lateral line scales; a longer slimmer body, with less arched dorsal and ventral contours; a more acute muzzle; smaller, more fragile fins; a more elongate caudal spot; obsolescent or absent predorsal dark mark and middorsal dark streak; the dorsal origin is slightly behind the pelvic insertion rather than the reverse; a lower pectoral ray count; and a much lower circumferential scale count. In practically all characters mentioned in this comparison xaeno- cephalus, roseus and petersoni are very much alike. Other differ- ences between asperifrons and roseus may be seen in the key. A detailed reading of Jordan's (1877: 355) original description of N. xaenocephalus with specimens of related species at hand shows clearly that he described the form recognized herein under that name. However, a re-examination of the two types, USNM 20116, which were designated as such in Jordan and Evermann (1896: 289), proves that Jordan had both N. xaenocephalus and N. asperifrons in his original material. We hereby designate as lectotype of N, xaeno- cephalus the specimen which measures 50.1 mm in standard length and retains the number USNM 20116. The single specimen of N. asperifrons has been recataloged as USNM 164969 and is designated as a paratype. Also examined was another series of three specimens originally bearing the number USNM 17886 collected by Jordan near Rome, Georgia and which were probably used at least in part in the original description of N. xaenocephalus. Two specimens 48.3 and 38.1 mm in standard length may be considered syntypes of xaeno- cephalus. The third specimen in this series is N. asperifrons, an adult 45.5 mm in standard length. It has been removed, designated as a paratype and recataloged as USNM 164968. The original description of N. xaenocephalus by Jordan (1877: 335) stated that "Two varieties or forms may be appreciated, the one larger, stouter, and with a larger mouth and much larger eye. No. 1 Suttkus and Raney: A New Cyprinid 31 They seem, however, to shade into each other. They occur together in about equal abundance." Our study of adequate series of N. xaeno- cephalus (28 collections numbering 677 specimens) indicates that he was dealing with characters which represented the extremes in size, and also probably in age, and our observations of the characters of large specimens are similar to his. That these ontogenetic changes may be of considerable degree was demonstrated early in our study since in preliminary sorting of specimens, we believed that two species (not including asperifrons) were present. Gilbert (1891: 154) also overlooked N. asperifrons and mis- identified both roseus and asperifrons from the Black Warrior River system as xaenocephalus. In addition, he misidentified N. baileyi as chrosomus. Two series of N. baileyi housed in the United States National Museum were the basis for Gilbert's (1891: 154), records of N. chrosomus from a tributary of the Black Warrior River near Tuscaloosa, Alabama. The data for the two series are as follows: USNM 125079 (1, 43), Black Warrior R, Tuscaloosa, Ala., May 21, 1889, collected by P. H. Kirsch and USNM 36690 (10, 39-47) North R., Tuscaloosa, Ala., collected by C. H. Gilbert and Joseph Swain (presumably in 1884). Since the description of Notropis baileyi appeared, two additional lots have been discovered in the University of Michigan, Museum of Zoology, by Reeve M. Bailey. The data for these two series, fur- nished by him, are as follows: UMMZ 111121 (24, 33-55), 6 mi. W. Auburn, Wire Road, Alabama, June 29, 1930; UMMZ 111124 (2 adults), Willmore Dam, September 13, 1930. Notropis asperifrons and N. xaenocephalus have also been taken together in three collections now housed at Cornell. The collections were made by Robert H. Gibbs and Philip P. Caswell in mid-June 1952. Both were found at the type locality of asperifrons in Murray Co., Georgia and at two places in Alabama: a tributary of Terrapin Cr. at the Cherokee-Calhoun county line on Alabama Hwy. 74 and in Cheaha Cr., 3-3 mi. S.W. Mumford on U.S. Hwy. 421. Although their ranges overlap, asperifrons was taken downstream in the Coosa River system, where xaenocephalus was not captured. We also have 27 collections of the latter, without asperifrons, from the tributaries of Coosa and Etowah rivers in Bartow, Cobb, Gordon, Dawson, Floyd, Lumpkin, Murray, Pickens, and Whitfield counties in north Georgia. The types of Jordan's (1877: 61) "Luxilus roseus," taken in Natal- bany R. near Tickfaw, La., were examined. Nineteen specimens representing two genera and four species were present in the series, USNM 17831. Eight specimens of Notropis roseus which measured from 36.5 to 53.5 mm in standard length were included. The largest specimen is hereby designated as lectotype. Although the teeth are missing from the left side, those on the right are 4,2 and in other respects it is a typical example of roseus. The other eleven specimens in the "type" series were identified and recataloged as follows: Notropis venustus (Girard), 1 spec, 26.5 mm recataloged as USNM 32 Tulane Studies in Zoology Vol. 3 163569; Notropis cornutus (Mitchill), 9 spec, 237-38.4 mm re- cataloged as USNM 163570; Hybopsis amblops (Rafinesque), 1 spec, 47.7 mm recataloged as USNM 163571. The relationships of N. hypsilepis and the allopatric asperifrons, both of which were probably derived from roseus, are close. The development of an inferior mouth seems to be an adaptation for life on or near the bottom. These two forms may be separated easily by reference to the many characters used in the key; asperifrons is dark and elongate whereas hypsilepis is light-colored and relatively deep bodied; the back at the dorsal fin base is light posteriorly in hypsi- lepis whereas it is dark in asperifrons. Their relationships are indi- cated by the presence in each of a vertical row of nuptial tubercles on the anterior lateral line scales and elevated anterior lateral line scales. The following combinations of characters will serve to separate hypsilepis from the other species of Notropis, (asperifrons, xaeno- cephalus, roseus, and peter soni) in the same general geographical area, with 7 anal rays and 2, 4 — 4, 2 teeth: Body light colored rather than darkish. Contrasting dark patches on the body at the dorsal and anal fin bases limited to the base of the first 4 or 5 rays and thus appear as blotches rather than being distributed along the entire base. Melanophores absent immediately behind or beside the anus. The dark lateral band weak anteriorly but present posteriorly, rather than being strongly developed throughout its length. The basicaudal spot definitely separated from the lateral band, rather than being continuous or only slightly separated (peter soni); wedge-shaped and narrow, being no wider than three caudal rays at its posterior and rather than being quadrate, or, if wedge-shaped, as wide as five or six caudal rays. The upper lip light on its posterior two-thirds, and the lower lip white rather than dusky or black in whole or part. The characters given in the key will suffice for separating asperi- frons from baileyi, which also has 2, 4 — 4, 2 teeth and 7 anal rays. As Suttkus and Raney (1955a) have pointed out, the relationships of baileyi are with lutipinnis and chrosomus. References Cited Bailey, Reeve M., Howard Elliott Winn and C. Lavett Smith 1954. Fishes from the Escambia River, Alabama and Florida, with ecologic and taxonomic notes. Proc. Acad Nat. Sci., Phila., 106: 109-164, 1 fig. Gilbert, Charles H. 1891. Report of explorations made in Alabama durirg 1889 with notes on the fishes of the Tennessee, Alabama and Escambia rivers. Bull. U. S. Fish Comm., 9 (1889) : 143-159, 2 figs. Hubbs, Carl L. and Karl F. Lagler 1947 (and second printing, 1949). Fishes of the Great Lakes region. Bull. Cranbrook Inst. Sci., 26: i-xi, 1-186, many figs. Jordan, David Starr 1877. A partial synopsis of the fishes of upper Georgia. Ann. N. Y. Lyceum Nat. Hist, 11: 307-377. 1877. Contributions to North American ichthy- No. 1 Suttkus and Raney: A New Cyprinid 33 ology. A. Notes on Cottidae, Etheostomidae, Percidae, Centrar- chidae, Aphredoderidae, Dorysomatidae and Cyprinidae, with revisions of the genera and descriptions of new or little known species. Bull. U. S. Nat. Mus., 10: 1-68. Jordan, David Starr and Barton Warren Evermann 1896. The fishes of North and Middle America. . . . Bull. U. S. Nat. Mus., 47, Pt. 1: i-ix, 1-1240. Suttkus, Royal D. and Edward C. Raney 1955a. Notropis baileyi, a new cyprinid fish from the Pascagoula and Mobile Bay drain- ages of Mississippi and Alabama. Tulane Stud. Zool., 2 (5) : 69-86, 4 figs., 1 map. 1955b. Notropis hypsilepis, a new cyprinid fish from the Apalachicol'a River system of Georgia and Alabama. Tulane Stud. Zool, 2 (7) : 159-170, 2 figs., 1 map. 'r* If[<.vr<^'[e,±»SJ Volume 3, Number 2 August 1, 1955 A NEW LOUISIANA COPEPOD RELATED TO DIAPTOMUS (AGLAODIAPTOMUS) CLAVIPES SCHACHT (COPEPODA, CALANOIDA) MILDRED STRATTON WILSON, ARCTIC HEALTH RESEARCH CENTER, U. S. PUBLIC HEALTH SERVICE, ANCHORAGE, ALASKA MOS. COMP. ZOOL LIBRARY Blip 1 * W5 HARVARD UNIVERSITY TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the area bordering the Gulf of Mexico anc3 the Caribbean Sea. Each number is issued separately and deals with an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Robert W. Pennak, Professor of Zoology, University of Colo- rado, Boulder, Colorado " David Causey, Professor of Zoology, University of Arkansas, Fayetteville, Arkansas Walter G. Moore, Professor of Biology, Loyola University, New Orleans, Louisiana Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers may be purchased by individuals, but subscriptions are not accepted. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers to the editor. Re- mittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zool. Price for this number: $0.30. Assistants to the Editor: Carol L. Freret Donald W. Tinkle George Henry Penn, Editor, Meade Natural History Library Tulane University, New Orleans, U. S. A. LIBRARY AUG 1 5 1955 HARVARD A NEW LOUISIANA COPEPOD RELATED TO DIAPTOfyllMNWIV (AGLAODIAPTOMUS) CLAV1PES SCHACHT (COPEPODA, CALANOIDA) MILDRED STRATTON WILSON, Arctic Health Research Center, U. S. Public Health Service, Anchorage, Alaska Study of new collections from small bodies of fresh water in Louisi- ana continues to reveal species of copepods new to science as well as species as yet unrecorded for the state. The present report describes the fourth new Louisiana species to be added recently to the list of North American diaptomid copepods. Others are Diaptomus louisi- anensis M. S. Wilson and Moore (1953a), D. bogalusensis M. S. Wilson and Moore (1953b) and D. moorei M. S. Wilson (1954). It is also of interest to note that the type localities of two other diaptomid copepods are in Louisiana. Of these, D. conipedatus Marsh (1907) has not yet been reported from outside the state. D. dorsalis Marsh (1907) is now known to be fairly common in the southeastern states and also to occur in the West Indies. Kiefer (1936) recorded it from Haiti as a new species, D. proximus. Kiefer's description is more detailed than that of Marsh and comparison of it with type material of dorsalis in the United States National Museum shows that differences noted by Kiefer were omitted from the original descrip- tion. The species also occurs in Puerto Rico having been identified by myself in a U. S. National Museum collection from Guanica Lake. D. dampfi Brehm (1932, 1939) from Lake Peten, Guatemala, is closely allied to dorsalis and may or may not be synonymous. Brehm's descriptions are too incomplete to allow for a satisfactory decision on the basis of his papers alone. The occurrence of dorsalis throughout the southeastern United States and the West Indies, and its possible presence in Central America, suggests that these new species should be looked for through- out this relatively little known area. Neither the recently discovered species nor the older conipedatus should be considered endemic to Louisiana on the basis of present knowledge. Although there may well be extreme localization of some species in the southeastern part of the continent, recent studies have extended the range of species that for many years were considered localized or rare, and no con- clusions should be drawn until an intensive survey of the region has been made. One of the new species {moorei) is already known from eastern Texas. Anyone studying Louisiana diaptomids, should also note the new species recently found in neighboring areas: D. sinuatus Kincaid (1953), a form closely allied to bogalusensis, from Panama City, Florida; D. marshianus M. S. Wilson (1953) from Lake Jackson, Florida; and D. texensis M. S. Wilson (1953) from Aransas County, Texas. Kiefer (1936: 309) summarized the literature dealing with the 38 Tulane Studies in Zoology Vol. 2 free-living fresh and brackish water copepods of this region (West Indies, Florida west to Texas, Mexico and Central America). Since then, records of distribution of such copepods in this general region are found in papers by C. B. Wilson (1936, 1938), Kiefer (1938), Pearse (1938), Brehm (1939), Harkness and Pierce (1940), Osorio Tafall (1941, 1942a, b, 1943), Coker (1943), Yeatman (1944), Penn (1947), Pierce (1947), Davis (1948), Dickinson (1949), King (1950), Davis and Williams (1950), Comita (1951), Hoffman and Causey (1952), Kincaid (1953), Peckham and Dineen (1953), M. S. Wilson (1941, 1953, 1954) and M. S. Wilson and Moore (1953a, b). I am indebted to Dr. James E. Sublette of Northwestern State Col- lege, Natchitoches, Louisiana, who made the collections of the new species upon which this study is based, and to Dr. Walter G. Moore of Loyola University who referred the collections to me. Specimens of Diaptomus clavipes Schacht used for comparative study were from the collections of the United States National Museum and the Illinois Natural History Survey. DIAPTOMUS (AGLAODIAPTOMUS) CLAVIPOIDES, sp. nov. Specimens Examined. — Type lot: five hundred adults of both sexes, many females ovigerous and with attached spermatophores; seasonal pond near Grand Ecore, Natchitoches Parish, Louisiana, March 23, 1954, J. E. Sublette. Associated with D. moorei M. S. Wilson. Holo- type 9, United States National Museum catalog number 97230, allo- type $ , number 97231. One hundred adults of both sexes, same locality, May 31, 1954. Diagnosis. — With these characters of the subgenus Aglaodiaptomus: Two setae on segment 11 of female and left male antennules. Right antennule male, segment 14 without spinous process but with pro- cesses on segments 15 and 16. Maxilliped with three setae on distal lobe of basal segment. Leg 2, Schmeil's organ present on endopod segment 2 of both sexes. Leg 5 of female, third segment of exopod imperfectly separated; two well developed, thickly plumose setae on apex of endopod. Leg 5 of male, left exopod of the leptopus form with narrow distal segment and closely set, apical processes; the outer process digitiform, the inner a much longer curving seta. Length, 2 2.3-2.5 mm. $ 2.0-2.13 mm. Greatest width of meta- some in both sexes in mandibular area of cephalic segment. Meta- some segments 5 and 6 separated only by short lateral suture. Metasomal wings of female not laterally expanded and with slight asymmetry; each wing with moderately developed inner lobe not reaching beyond that of the outer portion, that of the left a little larger than that of the right ( fig. 2 ) ; in dorsal view, this difference is hardly noticeable (fig. 1). Urosome of female two-segmented (fig. 1); genital segment with very slight lateral symmetrical swell- ing; caudal rami shorter than anal segment ( segments 2 -f- 3 ) , hairs on inner margin only. Ova numerous, average number per ovisac 26. Urosome of male symmetrical except for backwardly produced portion No. 2 Wilson: New Louisiana Copepod 39 Figures 1-9. Diaptomus clavipoides, sp. nov., female: 1. metasomal segments 5-6 and urosome, dorsal view, ovigerous specimen with two attached spermatophores; 2. right (top) and left metasomal wings, lateral view (arrows indicate outer edge) ; 3. setae of antennule seg- ments 19-20, with detail of apex; 4. leg 5, with detail exopod setae. Male: 5. spermatophore, dissected out from body; 6. right antennule, spines and processes of segments 10-16; 7. same, apical segments 23-25; 8. leg 5, right basipod 2, profile view of processes of mid- posterior face; 9. leg 5, posterior view. Figure 10. Diaptomus clavipes Schacht: male, right leg 5, posterior view (from slide in type lot, Illinois Natural History Survey collec- tion.) 40 Tulane Studies in Zoology Vol. 2 of right side of segment 4. Spermatophore somewhat angled near its proximal third and curved in the midportion (fig. 5); when attached to the female and viewed dorsally, it appears strongly curved to the right (fig. 1). Antennules of both sexes reaching to near middle of urosome; those of the female and left side of the male with two setae on segment 11, and one on segments 13-19; setae of segments 17, 19, 20 and 22 shorter than the length of their segments, stiff, their tips not bent into a hook, though sometimes slightly curved ( fig. 3 ) ■ Right anten- nule of male (fig. 6) with spine of segment 8 not enlarged, that of 13 longer than that of 11, outcurved. Proportions of spines to the segmental width and to one another: Segment 10 11 13 Segment width 23 23 35 Spine length 16 25 33 Strong spinous processes at midpoint of segments 15 and 16. Seg- ment 23 (fig. 7) with short (length subequal to segment width), thick process strongly directed outward; a hyaline membrane along entire margin of segment to base of process. Leg 5, female (fig. 4). Exopod 3 not developed. Lateral seta of segment 2 lacking. Outer seta of exopod 3 a stout, flat spine; the inner a plumose seta at least twice the length of the outer. Endopod reaching to end of first exopod segment or beyond; the terminal setae with widened bases and thickly plumose margins, their length about half that of the endopod. Leg 5, male (fig. 9). Left leg reaching from just above middle of right exopod 2 to a little beyond. Basal sensilla of both legs short, slender spines. Midposterior face of right basipod 2 (fig. 8), with a proximal rounded lobe and a large distally placed process which reaches to near the end of the first exopod segment and consists of a curved spinous portion and an inner membrane; proximally the inner margin of the segment is produced into a prominent process bent at its middle into an obliquely directed spiniform portion. Rela- tive proportions of outer margins of right basipod 2 and exopod segments 1 and 2, 39:32:45. Lateral spine of right exopod 2 placed near distal end, its length a little less than width of segment, 20:23. Claw longer than exopod, 85:77, enlarged basally, tapered abruptly beyond basal swelling so that it is very slender throughout, the tip usually recurved. Left basipod and exopod subequal to one another. Relative lengths of outer margins of exopods 1 and 2, 20:22. Left exopod 1 swollen medially, with extensive hairy pad. Left exopod 2 comparatively much reduced in width, its length about three times its width; processes terminally placed close together, the inner seta at least twice the length of the outer digitiform process, about 20:9. Right endopod reduced, reaching to proximal fourth or third of exo- pod 1. Left endopod elongate, reaching beyond middle of exopod 2. No. 2 Wilson: New Louisiana Copepod 41 Systematic Discussion This new species is closely allied to Diaptomus clavipes Schacht (1897). The following notes comparing the characters of the two species are based upon study of a large number of specimens of both. Several collections of clavipes have been examined. Most of these are listed under the section "Distribution" as new records. In addition, some slides from the type lot in the Schacht collection, Illinois Natural History Survey have been studied, as well as whole specimens of D. nebraskensis Brewer (1898) from the type lot in the U. S. Na- tional Museum. As has been long recognized, Brewer's name is synonymous with clavipes. Relationship of the two species is shown by both sexes. They do not vary widely from one another in total length range, and both have stout bodies and appendages. The females are very similar to one another, but exhibit several constant differences which are considered to be of specific value in these as well as in other diaptomids. In both species, the urosome is two-segmented and the genital segment is without noticeable lateral protrusions. Their differences are: ( 1 ) Metasome: greatest width in the mandibular area of the cep- halic segment in clavipoides; in the second segment in clavipes. ( 2 ) Metasomal wings: with moderately developed inner lobes and of nearly same size in clavipoides; lacking inner lobes in clavipes and with the left wing more produced posteriorly than the right. (3) Antennule: setae of segments 17, 19, 20 and 22 with un- hooked ends in clavipoides; with hooked ends in clavipes. (4) Leg 5: lateral seta of exopod 2 lacking in clavipoides; pres- ent in clavipes. The structure of the fifth leg in the male is quite indicative of the close relationship of the two species. Each has on the posterior medial face of the right second basipod segment a proximal lobe and a large distal process. Comparable armature is found in other aglaodiapto- mids {leptopus, spatulocrenatus, conipedatus) but the distal process is much smaller in them. D. clavipes and clavipoides are further distinguished from these species by the presence of the mesially di- rected process on the inner basal portion of this segment. It is in the same position in the two species, but differs in size and shape. In clavipes, it is comparatively small (its width about 13-15 percent of the length of the inner margin of the segment) and protrudes di- rectly outward from the segment. In clavipoides, there is a stout basal portion with a nearly equally large, obliquely directed spiniform apex; its width is about 24-25 percent of the total length of the inner margin of the segment. In clavipes there is also a smaller process placed distad to the basal process near the middle of the segment (fig. 10). This second process is lacking in clavipoides. Other noticeable differences are the more reduced right endopod of clavi- poides, and the greater length of the claw. In clavipes, the endopod 42 Tulane Studies in Zoology Vol. 2 usually reaches to near the middle of the first segment of the exopod, and the claw is shorter than the exopod. The left antennule of the male of clavipoides agrees with those of the female in having straight setae on segments 17, 19, 20 and 22; these were hooked in all the various collections of clavipes that were examined. The right antennule in these two species is similar in the armature and relative lengths of the spines of segments 8-16. The apical process of segment 23 was invariably present in the numerous specimens of clavipoides, all of which were checked for this char- acter, but it was not found in specimens of clavipes, nor has it been recorded in literature for this species. In both, there is a lateral hyaline membrane along the entire margin of the segment; in clavipes, this membrane is very strongly developed with a well rounded apex. The spermatophores attached to the female genital segment and also some dissected out from the body of the male, were bent near the base and curved as shown in figures 1 and 5. In the specimens of clavipes that were examined, the spermatophore is nearly straight and unangled as is usual in Diaptomus. What significance, if any, attaches to this unusual shape in clavipoides, is not known. On the basis of the type lot it is a character of distinction from clavipes and one that should be carefully checked in future studies of the species and other aglaodiaptomids. The differences between the males of the two species may be sum- marized as follows: ( 1 ) Leg 5, right: Second basipod segment, inner proximal process with enlarged basal portion and obliquely directed apex in clavipoides; without enlarged basal portion and the apex directed mesially in clavipes; no small process distad to proximal process in clavipoides, present in clavipes. Claw longer than exopod in clavipoides; shorter than exopod in clavipes. Endopod short in clavipoides (about one- fourth to one-third of length of inner margin of exopod 1 ) ; longer in clavipes (nearly one-half of exopod 1). (2) Antennule: Left, setae of segments 17, 19, 20 and 22 with straight end in clavipoides; with hooked end in clavipes. Right, seg- ment 23 produced into outwardly directed process and with length- wise membrane in clavipoides; with membrane only in clavipes. (3) Spermatophore: bent near base and curved in clavipoides; without such distinct curvature in clavipes. Because of the seemingly close relationship of the new species to clavipes, particular attention was paid in study of specimens to the possible existence of variation in the characters by which the two forms are separated. Dissections of twenty specimens of both sexes of clavipoides, and of the same number of clavipes from a single sample (Baja California) were checked for variation in the stated diagnostic differences in the antennules and the fifth legs. In addi- tion, these were further checked on two to five specimens of clavipes from each of the new collection records listed herein. No variation No. 2 Wilson: New Louisiana Copepod 43 was found in either species in any of the "present-absent" characters such as the lateral seta of the second exopod segment of the female fifth leg, the apical hook on certain antennular setae, the process of segment 23 of the male right antennule, and the small medial process of the right second basipod segment of the male fifth leg. In the "quantitative" characters such as the comparative size of the proximal process of the inner margin of the second basipod segment, the claw and endopod of the male right fifth leg no intermediate condition or overlap was found. Those characters for which dissection was un- necessary for observation, such as the attached spermatophore, the shape of metasome and wings, the apex of the antennular setae and the process of segment 23 of the male right antennule, were also checked on all the available whole specimens and no variation found. Some of the structural characters of clavipoides are of considerable taxonomic interest. Among these is the lack of development of the third exopod segment and the absence of the lateral seta of the second exopod segment of the female fifth leg. From species to species and also within individual species in the subgenus Aglaodiaptomus, there is considerable variation in the de- gree of development and the distinctness of separation of the third segment, but clavipoides is the only species in which I have observed the apparently constant combination of complete loss of both the third segment and the seta of the second segment. This is a dis- tinctive character of three related North American subgenera, Lepto- diaptomus, Onychodiaptomus and Skistodiaptomus. Between these subgenera and the common western and northern subgenus Hespero- diaptomus, the aglaodiaptomids are an intermediate group. This intermediate position is well emphasized in clavipoides in the reduc- tion in the exopod of the female fifth leg. The straight tips of the setae on certain segments of the female antennules and on the left antennule of the male in clavipoides have been particularly noted because in most of the species of the subgenus Aglaodiaptomus these setae have a characteristic hooked tip. Al- though small, this hook is distinct enough to be noticeable in undis- sected specimens under low power of the microscope. The variability of such a character might be questioned, but I have never found the hook lacking in large numbers of specimens of all the species con- cerned from a wide geographical range. The only species of the subgenus other than clavipoides in which this hook is not present is D. stagnalis, which also differs in several other details from the con- ditions usual in other aglaodiaptomids and has no near relative among the known species. Most of the species of the subgenus Aglaodiaptomus have only 1 seta on each of segments 13-19. Those in which 2 setae are found on some segments are stagnalis (2 on 14, 16, 18, 19) and lintoni and forbesi (2 on 16). Occasionally, in this group as in other diaptomids having two setae on segment 11, an extra seta may be present on a segment which normally has only one. I have never observed in the 44 Tulane Studies in Zoology Vol- 2 female such a seta on both antennules of a pair. This asymmetry coupled with the comparative rarity, makes this condition appear as an anomaly comparable to the occasional multiplication of other setae, claws or structures that have been noted in several appendages in all diaptomid groups. Among a large number (117) of female clavi- poides carefully checked for antennal setation, two instances of such anomaly were found. One individual had two setae on segment 13 of the right antennule, another had two on segment 19 of the left; in each instance the corresponding segment of the opposite antennule was normal. Distribution D. clavipes was described from Iowa, and this is still the farthest eastern record. The summary of its distribution given by Marsh (1929) included records from only a few other states (Nebraska, Colorado, Texas). Since then, other records have extended or ampli- fied its distribution: Oklahoma (Duck, 1937), Kansas (Leonard and Ponder, 1949; Ratzlaff, 1952); Texas and northern Mexico (Comita, 1951); Arizona, New Mexico, Montana (Kincaid, 1953); eastern Texas (M. S. Wilson, 1954). The Light accession in the United States National Museum con- tains several collections of clavipes which further amplify its occur- rence in southwestern United States and Mexico. These were all identified by Dr. Light, but have been verified in connection with the present study. The data with collections and associated calanoid species are as follows: Arizona: Small dammed reservoir in edge of hills, one mile south of Payson, Gila Co., May, 1935, S. F. Light, elevation 4800 feet; Coolidge Dam, San Carlos Lake, Gila Co., May, 1935, S. F. Light, elevation 2400 feet, with D. siciloides; Annex Lake, Coconimo National Forest, Coconimo Co., May 26, 1934, S. Wright, with D. nudus; About 10 miles north of Williams, Coconimo Co., May 15, 1937, A. Michelbacher, elevation 6690 feet, with D. nudus. Nevada: Mead Lake, in deep water above dam, Clark Co., April, 1937, A. Michelbacher, with D. siciloides. New Mexico: A prairie lake near Clovis, Curry Co., July, 1941, Kathryn Buchanan, with D. siciloides; Another lake, same data, with D. (Mastigodiaptomus) albuquerquensis. Texas: Small artificial lake at Baird, Callahan Co., July, 1936, S. Wright, with D. siciloides. Mexico: Tank, 20 miles northeast of Cumondu, Baja California, July 21, 1938, A. Michel- bacher and E. Ross, with D. novamexicanus; Presa de Hipolito, Coa- huila, May 11, 1941, E. S. Deevey, with D„ siciloides. The common diaptomid association in these instances is with a species of the subgenus Leptodiaptomus. Such is also true in the oc- currence of clavipoides with D. (L.) moorei. This latter species was also found in eastern Texas with clavipes (M. S. Wilson, 1954). In present knowledge, therefore, the distribution pattern of clavipes includes the lower altitudes of the Rocky Mountains in the United States and neighboring areas of northern Mexico, the nearby south- No. 2 Wilson: New Louisiana Copepod 45 western states and those east to the Mississippi River. Its most west- ern occurrence is in Baja California, Mexico. At present there are no known records from the state of California. The Nevada record given above is on the border of Arizona. Whether the species is generally spread in the western Mississippi Valley is still to be investigated. It can not be called a rare species, and its occurrence at widely ranging altitudes and in diverse bodies of water, such as lakes, reservoirs, ponds and roadside ditches, suggests both a much more common oc- currence than now recorded and in part, at least, a fortuitous type of dispersal. The comparative distribution patterns and associations of closely related species of diaptomids have been little considered in North America. We do not actually know what significance attaches to geographic distribution in relation to the taxonomy of diaptomid copepods. As a result of my studies, I have come to the conclusion that it may well be a very useful tool in the interpretation of taxonomy both in relation to the status of forms and the evaluation of char- acters. Of particular importance is the study of closely allied species (M. S. Wilson, 1953: 2). When thoroughly known, the comparative distribution patterns, associations and characters of these two aglao- diaptomid species may be of instructive value in the taxonomy of the group. Quite possibly, the two may be macrogeographically sympatric in the lower western Mississippi Valley and westward into Texas. This is already suggested by the presently known distribution of clavipes and the association of both species with D. moorei within a rather close geographic range as represented by the eastern Texas record of clavipes and the type locality of clavipoides in western Lou- isiana. The distribution of the latter species may be more localized or restricted than that of clavipes, but no conclusions on the presence or absence of either species can be reached until the region involved has been thoroughly surveyed. References Cited Brehm, Vincenz 1932. Notizen zur Siisswasserfauna Guatemalas und Mexikos. Zool. Anz., 99: 63-66. 1939. La Fauna microscopica del Lago Peten, Guate- mala. Ann. Escuela Nac. Cienc. Biol., 1: 173-202. Brewer, Albert D. 1898. A study of the Copepoda found in the vici- nity of Lincoln, Nebraska. Jour. Cincinnati Soc. Nat. Hist., 19: 119-138. Coker, R. E. 1943. Mesocyclops edax (S. A. Forbes), M. leuckarti (Claus) and related species in America. Jour. Elisha Mitchell Sci. Soc, 59(2) : 181-200. Comita, Gabriel W. 1951. Studies on Mexican copepods. Trans. Amer. Micros. Soc, 70(4) : 367-379. Davis, Charles C. 1948. Notes on the plankton of Long Lake, Dade County, Florida, with descriptions of two new copepods. Quart. Jour. Fla. Acad. Sci., 10(2-3) : 79-88. Davis, Charles C. and Robert H. Williams 1950. Brackish water plankton of mangrove areas in southern Florida. Ecology, 31: 519-531. 46 Tulane Studies in Zoology Vol. 2 Dickinson, J. C, Jr. 1949. An ecological reconnaissance of the biota of some ponds and ditches in northern Florida. Quart. Jour. Fla. Acad. Sci., 11(2-3): 1-28. Duck, Lester G. 1937. Some copepods of Oklahoma. Proc. Oklahoma Acad. Sci, 17: 34-35. Harkness, W. J. K. and E. L. Pierce 1940. The limnology of Lake Mize, Florida. Proc. Fla. Acad. Sci., 5: 96-116. Hoffman, Carl E. and David Causey 1952. Limnological studies in Arkansas. I. Physico-chemical and net plankton studies of Lake Fort Smith in its fourth year of impoundment. Proc. Arkansas Acad. Sci., 5: 55-72. Kiefer, Friedrich 1936. Frielebende Suss- und Salzwassercopepoden von der Insel Haiti. Archiv. Hydrobiol., 30: 263-317. 1938. Ruderfusskrebse (Crust. Cop.) aus Mexiko. Zool. Am., 123: 274-280. Kincaid, Trevor 1953. A Contribution to the Taxonomy and Distri- bution of the American Fresh-water Calanoid Crustacea. Callio- stoma Co., Seattle, 73 pp. & Addendum, P. 74. King, Joseph E. 1950. A preliminary report on the plankton of the west coast of Florida. Qttart. Jour. Fla. Acad. Sci., 12(2) : 109- 137. Leonard, A. B. and L. H. Ponder 1949. Crustacea in eastern Kansas. Trans. Kansas Acad. Sci., 52: 168-204. Marsh, Charles Dwight 1907. A revision of the North American species of Diaptomus. Trans. Wise. Acad. Sci., Arts, Lttrs., 15(2): 381-516. 1929. Distribution and key of the North American copepods of the genus Diaptomus, with the description of a new species. Proc. U. S. Nat. Mus., 75(14) : 1-27. Pearse, A. S. 1938. Copepoda from Yucatan Caves. Carnegie Inst. Wash., Publ. 491: 153-154. Peckham, Richard S. and Clarence F. Dineen 1953. Summer plank- ton of Lake Amatitlan, Guatemala. Amer. Midi. Nat., 50(2) : 377- 381. Penn, George Henry 1947. Branchiopoda and Copepoda of the New Orleans area as recorded by Ed Foster in the early 1900's. Proc. Louisiana Acad. Sci., 10: 189-193. Pierce, E. L. 1947. An annual cycle of the plankton and chemistry of four aquatic habitats in northern Florida. Univ. Fla. Studies, Biol. Sci. Ser., 4(3): 1-67. Schacht, Frederick W. 1897. The North American species of Diapto- mus. Bull. Illinois State Lab. Nat. Hist., 5(3) : 97-208. Ratzlaff, Willis 1952. The limnology of some roadside ditches in Chase and Lyon Counties, Kansas. Emporia State Res. Stud., 1(1): 5-32. Tafall, B. F. Osorio 1941. Diaptomus cuauhtemoci nov. sp. de la mesa central de Mexico. Ciencia (Mexico), 2: 296-298. 1942a. Un nuevo "Diaptomus" del Mexico central (Copepoda, Diaptomidae). Rev. Brasil Bio., 2(2): 147-154. 1942b. Diaptomus ( Microdiaptomus) cokeri, nuevos subgenero y especie de Diaptomido de las cuevas de la region de Valles (San Luis Potosi, Mexico) (Copep., Calan.). Ciencia (Mexico), 3: 206-210. 1943. Observationes sobre la fauna acuatica de las cuevas de la region de Valles, San Luis Potosi (Mexico). Rev. Soc. Mex. Hist. Nat., 4: 43-71. No. 2 Wilson: New Louisiana Copepod 47 Wilson, Charles Branch 1936. Copepods from the cenotes and caves of the Yucatan Peninsula, with notes on cladocerans. Carnegie Inst. Wash., Publ. 457: 77-88. 1938. Copepoda from Yucatan caves. Carnegie Inst. Wash., Publ. 491: 153-154. Wilson, Mildred Stratton 1941. New species and distribution rec- ords of diaptomid copepods from the Marsh collection in the United States National Museum. Jour. Wash. Acad. ScL, 31: 509-515. __ 1953. New and inadequately known North American species of the copepod genus Diaptomus. Smithsonian Misc. Coll., 122(2) : 1-30. 1954. A new species of Diaptomus from Louisiana and Texas with notes on the subgenus Leptodiaptomus. Tulane Stud. Zool, 2(3) : 49-60. Wilson, Mildred Stratton and Walter G. Moore 1953a. New rec- ords of Diaptomus sanguineus and allied species from Louisiana, with the description of a new species (Crustacea: Copepoda). Jour. Wash. Acad. Sci., 43(4) : 121-127. _ _ 1953b. Diagnosis of a new species of diaptomid copepod from Louisiana. Trans. Amer. Micros. Soc, 72(3) : 292-295. Yeatman, Harry Clay 1944. American cyclopoid copepods of the viridis-vernalis group (including a description of Cyclops carolini- anus n. sp.). Amer. Midi. Nat., 32(1) : 1-90. ////- /t^ (7f /SATJ^ "5P is id as Volume 3, Number 3 August 30, 1955 A NEW SPECIES OF STERNOTHERUS WITH A DISCUSSION OF THE STERNOTHERUS CARINATUS COMPLEX (Chelonia, Kinosternidae ) DONALD W. TINKLE, DEPARTMENT OF ZOOLOGY, TU LATHE UNIVERSITY, NEW ORLEANS, LOUISIANA and ROBERT G. WEBB, DEPARTMENT OF ZOOLOGY, UNIVERSITY OF KANSAS, LAWRENCE, KANSAS MliS. CUP. ZOQL LIBRARY SEP 9 1955 HARVARD UNIVERSITY TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the area bordering the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and deals with an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Hobart M. Smith, Professor of Zoology, University of Illinois, Urbana, Illinois. Norman Hartweg, Curator of Amphibians and Reptiles, Mu- seum of Zoology, University of Michigan, Ann Arbor, Michigan. Ernest E. Williams, Assistant Professor of Biology, Harvard University, Cambridge, Massachusetts. Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers may be purchased by individuals, but subscriptions are not accepted. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers to the editor. Re- mittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zool. Price for this number: $0.50. George Henry Penn, Editor, c/o Department of Zoology, Tulane University, New Orleans, U. S. A. Assistants to the Editor: Carol L. Freret Donald W. Tinkle MUS. COMP. M , LIBRARY SET ^ 195 KARVAPO A NEW SPECIES OF STERNOTHERUS WITH A DISCUS$IO]![ft;jy[; ;^TY OF THE STERNOTHERUS CARINATUS COMPLEX (Chelonia, Kinosternidae ) DONALD W. TINKLE, Department of Zoology, Tulane University, New Orleans, Louisiana and ROBERT G. WERE, Department of Zoology, University of Kansas, Lawrence, Kansas Tulane University field crews under the supervision of Dr. Fred R. Cagle and supported by a grant from the National Science Foundation have done much to clarify the status of turtle populations in the rivers of the north Gulf coast (Cagle, 1952, 1953, 1954). The collecting techniques developed, such as that described by Chaney and Smith (1950), made possible the procurement of samples of Stemotherus from the major rivers along the Gulf coastal plain. These samples revealed the presence of an undescribed species in the upper reaches of the Black Warrior river above the Fall Line in Ala- bama which is defined and named herewith. The authors are indebted to Dr. Cagle for the opportunity provided of serving with the field crews; to Dr. Hobart M. Smith of the Uni- versity of Illinois for examining selected specimens; to Dr. William B. Davis of Texas A. & M. College for making available the holotype of Stemotherus peltifer and other material; to Dr. Wilfred T. Neill of the Ross Allen Reptile Institute, Dr. Albert Schwartz of the Charles- ton Museum and Dr. Ralph L. Chermock of the University of Ala- bama for the loan of material; and to Mrs. Roger Conant and Mrs. Fred R. Cagle for photographs. We are grateful, also, to the many students who worked with us in the field for their contribution of time and ideas. The name for the new species was suggested by Dr. E. S. Hathaway, emeritus professor of Zoology at Tulane University. Sizes referred to in the text are plastra lengths measured along the median longitudinal suture to the nearest tenth of a millimeter with a Vernier caliper. Sex in all Tulane (TU) specimens was determined by dissection. STERNOTHERUS DEPRESSUS, sp. nov. Holotype, — Tulane University number 16171, immature male, taken in the Mulberry Fork of the Black Warrier river, 9 miles east of Jasper, Walker County, Alabama, near the bridge crossing of U.S. highway 78, August 11-12, 1953, by Robert G. Webb and Donald W. Tinkle. Paratypes. — Tulane University numbers 15902 (12) and 16062 (10) and Museum of Comparative Zoology number 54023, 18 females and five males collected at the type locality in June and August, 1953; University of Alabama 52-1065, 8 miles south of Carbon Hill, Walker County, Alabama, June 14, 1952, by H. Boschung and L. Cooper. 54 Tulane Studies in Zoology Vol. 3 This latter paratype is the only adult specimen of the new species known to us. Twenty-five types and seven topotypes comprise the hypodigm. Type locality. — A sluggish tributary of the Black Warrior river. All specimens taken at night, except one, by trapping or hand collecting from crevices in submerged stumps and in detritus along the shore. Diagnosis and definition. — A species possessing a round, low cara- pace with flared marginals; obtuse vertebral angle; and a reticulated pattern of lines on the dorsum of the head. Adult with flat carapace, arched at the sides. Related to Sternotherus carinatus in having im- bricate carapace shields, by absence of light stripes on the head and neck, absence of barbels on the neck, and lack of lateral keels in juve- niles. There characters distinguish S. carinatus and S. depressus from 5". odoratus. Differing from S. c. carinatus by lacking a high vertebral keel, absence of spots on the head, and presence of a gular scute. Differing from S. c. peltifer by lacking dark stripes on the sides of the head and neck, by having a flatter carapace with a larger ratio between vertebral angle and carapace height. Differing from S. c. minor by absence of lateral ridge, by a low carapace in adults which is flat on top, and by the presence of a reticulated pattern on the head. Description of holotype. — Male; plastron length, 36.8 mm; maxi- mum carapace length (straight line), 59-9 mm; carapace height from abdominals to juncture of second and third vertebrals, 18.5 mm; cara- pace width at juncture of sixth and seventh marginals, 52 mm; maxi- mum head width, 12.6 mm; length of abdominal from axillary to inguinal periphery, 8.0 mm; interhumeral suture, 5.8 mm; interpectoral suture, 4.4 mm; interabdominal suture, 7.9 mm; interfemoral suture, 4.0 mm; interanal suture, 11.3 mm; length of mandibular symphysis, 6.0 mm; angle of keel at juncture of second and third vertebrals, 133°. Eleven marginals, the last two higher than any of the first nine. Ail vertebrals except first wider than long. Each carapace shield with dark streaks on a gray-green background. Center of each marginal with a radial light line distinct against the cloudy ground color. Plastron immaculate; gular scute single and small. Neck with seven broken, irregular thin lines on the dorsal and dorsolateral surfaces. Head pattern of fine, reticulated, and dark lines on a yellow -green ground color. The anterior surfaces of forelegs and posterior surfaces of hind legs with similar reticulate pattern. Tail with eight irregular dark lines converging distally. Horny beak of upper jaw with numer- ous, tangentially arranged, dark markings. Two chin barbels; no neck barbels. Description of paratypes. — Measurements of the smallest and largest of the topotypes are: plastron length, 18.7 and 36.4 mm; maximum carapace length, 33.4 and 53-4 mm; carapace height, 9.5 and 16.8 mm; carapace width 31-3 and 50.0 mm; head width, 7.3 and 11.8 mm; abdominal length, 3.3 and 8.2 mm. Measurements other than plastra lengths do not necessarily reflect the maximum in these topotypes. No. 3 Tinkle and Webb: New Sternotherus 55 The elevation of the tenth and eleventh marginals above the pre- ceding ones is more distinct in larger individuals. The dark mark- ings on the carapace may be radiating lines, spots or small blotches. The markings are reduced in some turtles, but never absent. The plastra are usually covered with a brown deposit of environmental origin which must be removed to reveal the immaculate scutes. The gular is variable in size and unpaired. Dark lines on the neck vary from five to 18, depending partially upon which are considered lines and which rows of tiny, sometimes united spots. The reticulated arrangement of dark lines on a light background gives the head a dendritic pattern, which is also present on the limbs. Dark tangential marks are universal on the beaks of both jaws. Dark lines present on the tail. The vertebral angle was measured with aluminum wire (1.2 mm diameter) which was bent around the keel of the carapace at the juncture of the second and third vertebrals. The angle formed was traced on paper and measured with a protractor. This method is a slight modification of that reported by Mosimann (1955). The variation in this angle was 113° to 132°. The size of the angle is generally directly correlated with the size of the turtle. The inherent error for measurements of S. c. carinatus and S. depressus, the forms representing the extremes of size of the angle, was two to four (mean 2.44 degrees) for the former and four to six (mean 4.75 degrees) for the latter. The error for the other forms presumably lies between these extremes. The adult paratype must be given special consideration. Its color pattern is identical with that of the holotype. The carapace is low, but flat and is arched at the sides, unlike any of the topotypes. Its combination of characters sets this turtle apart from adults of any other form in the Sternotherus carinatus complex. Measurements are as follows: plastron length, 55.8 mm; carapace length, 89.4 mm; carapace height, 26.7 mm; carapace width, 60.4 mm; interhumeral suture, 6.2 mm; interpectoral suture, 10.6 mm; interabdominal suture, 16.1 mm; interfemoral suture, 6.8 mm; interanal suture, 14.2 mm. Little variation of the differentiating characters exists in the para- typic series. All are similar to the holotype in general appearance, pattern and proportions. Range. — This species has been taken only from a two mile length of the Mulberry Fork of the Black Warrior river in the vicinity of the type locality, and from a stream in the Black Warrior drainage, eight miles south of Carbon Hill. Both localities are in Walker County, Alabama, above the fall line. Sternotherus depressus is un- doubtedly more widespread, and should be expected in Tennessee, particularly in the drainage of the Tennessee River. Its known dis- tribution presents a geographic puzzle. Collections made in the Black Warrior river in Greene and Tuscaloosa counties, Alabama, contain only S. c. peltifer which has not been found in the Black Warrior above the fall line where S. depressus occurs. 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Comparisons (Table 1). — Sternotherus depressus is an unusual turtle. The low carapace with flaring marginals gives the turtle the appear- ance of being dorsoventrally flattened, whence the specific name (fig. 1-4). The characteristic depression of the carapace has been placed on a quantitative basis by calculation of the ratio of carapace angle to carapace height. Sternotherus depressus, at least the juveniles, are strikingly different in this character from other members of the Ster- notherus carinatus complex (fig. 7). Another distinctive feature of young S. depressus is the shape of the carapace in outline as seen from dorsal aspect. The shape more closely approaches the form of a circle than does that of any other members of the genus. A ratio of carapace-length/carapace -width expresses this characteristic and demonstrates the differences in this character be- tween the members of the Sternotherus carinatus complex (fig. 8). The general shape of the carapace in cross section is important in distinguishing among juveniles in the S. carinatus complex (fig. 9). Though distinct in some features, Sternotherus depressus is most closely allied to S. c. peltifer in general appearance and totality of characters. Discussion. — Allopatric populations with some resemblances are usually considered to be subspecifically related. However, in this instance, the striking differences of S. depressus and the lack of evi- dence of intergradation make the elevation of this form to specific rank a more conservative procedure. Sternotherus depressus is almost as different in its peculiar characteristics from 5". carinatus and S. odoratus as the latter two are from one another. Further knowledge DEPRESSUS HL HL MINOR 14 PELTIFER - I 1 I CARINATUS -I 1 1 1 1 1 1 I ''lit 8 9 10 II 12 13 Figure 7. Comparison of carapace - angle/carapace - height ratios. Block diagram shows mean, two standard errors and two standard deviations. 58 Tulane Studies in Zoology VoL 3 of distribution and variation of S. depressus, as well as other members of the complex, may alter this tentative conclusion. The turtles referred to as Sternotherus carinatus peltifer fit the description of that form given by Smith and Glass (1947). We have compared our specimens with the holotype in the Texas Cooperative Wildlife Collection of Texas A. & M. College. This form was de- scribed as Sternotherus peltifer. Carr (1952) referred it to con- specificity with S. carinatus. Because S. c. peltifer is most closely related to S. depressus a re- description of the former is needed in order to evaluate its status and understand its relationships within the Sternotherus carinatus com- plex. We have available 24 specimens from which the following description was made. 1 1. B 23 | DEPRESSUS 1 MINOR BB ■ 14 I PELTIFER HEH&B 71 1 CARINATUS 1 i i i l l i ■ 00 1. 10 1.20 1.30 1.40 1.50 160 1.70 Figure 8. Comparison of carapace - length/carapace - width ratios. Block diagram shows means, two standard errors and two standard deviations. Status of Sternotherus c. peltifer Smith and Glass The holotype is similar in every detail to our specimens. Four of the latter are from the Coosa River above the fall line in Alabama, and the remainder from the Alabama and Black Warrior rivers below the Fall Line. The character of size of the axillary and inguinal scutes used by Smith and Glass (1947) holds for all specimens, i. e* in each these scutes are small and longer than broad. This character is of no value in differentiating S. c. peltifer and S. depressus. The striping on the sides of the head and neck is the best character for distinguishing S. c. peltifer from the majority of individuals of other forms in the complex (fig. 5-6). This striping occurs in occasional specimens of S. c. minor, but not to the extent characteristic of S. c. peltifer. The second, third and fourth vertebrals are broader than long in all individuals. This is true generally also of S. depressus. The length No. 3 Tinkle and Webb: New Sternotherus 59 rv jr»-*o*.v Figures 1-2. 1. (top) Iiolctvpc of Sternotherus depressus 2. (bot- tom) Adult parptype of Sternotherus depressus (Photographs by Mrs. Fred R. Cagle). * 60 Tulane Studies in Zoology Vol. 3 Figures 3-4. 3. (top) Sternotherus carinatus peltifer and S. de- pressus. Juveniles of approximately same size 4. (bottom) Front view of S. depressus showing flared marginals (Photographs by Isa- belle Hunt Conant). No. Tinkle and Webb: New Sternotherus 61 ^ Figures 5-6. 5. (top) Holotype of Sternotherus carinatus peltifer (Photograph by R. G. Webb) 6. (bottom) Juvenile S. c. peltifer from Black Warrior River, Tuscaloosa County, Alabama (Photograph by Isabelle Hunt (Tenant). 62 Tulane Studies in Zoology Vol. 3 30 20 10 0 30 20 I 0 0 ■ 30 40 10 20 30 40 50 Figure 9. Relative carapace shapes of juvenile representatives of each member of the Sternotherus carinatus complex. Height is shown on ordinate and width on abscissa. All specimens are of the same plastron lergth. of the median humeral suture is too variable to be of any diagnostic value. In general appearance, S. c. peltijer is most similar to S. c. carinatus because of the prominent median dorsal keel. This keel is never as high nor sharp as in the latter, and is completely lost in older individuals of S. c. peltijer which developed the arched carapace characteristic of S. c. minor. Lateral keels are absent, but in small individuals faint ridges are present on some of the costal shields. The carapace pattern is of dark lines on each shield radiating from the postero-dorsal corner. The plastra are immaculate. The dorsal surface of the head in all individuals below the Black Belt (Chermock, 1952) is marked with small dark spots which are sparse or absent in the nasal region. These spots predominate also in individuals above the Black Belt, but fusion of the spots and develop- ment of a partially reticulated pattern (like S. depresses) occurs in a few individuals. The gular is unpaired in all except one individual which lacks this scute. Two chin barbels are present; no barbels present on the neck. The ventral surface of the neck is well marked, but the pattern is variable from distinct longitudinal stripes to a reticulate or diffuse pattern of spots. In summary, S. c. peltijer is a musk turtle with a distinct middorsal keel which becomes reduced with increasing age; with no lateral keels; No. 3 Tinkle and Webb: New Sternotherus 63 Figure 10. Distribution of members of the Sternotherus carinatus complex. The symbols show actual localities from which material has been examined (star symbol is type locality of S. depressus) . Dotted line shows hypothetical distributions and solid line approximates the geographic position of the Fall Line. 64 Tulane Studies in Zoology Vol. 3 with unpaired gular; and with dark stripes on the sides of the head and neck. The range of this form cannot be definitely delimited on the basis of existing records. The holotype was taken in the Pascagoula River drainage of central Mississippi. Two trips to the type locality failed to reveal the presence of S. c. peltifer in the area, but numerous S. odoratus were collected there. Intensive work on the Pascagoula river and seining in other rivers, streams and ponds in Mississippi has not produced additional specimens. Only S. c. carinatus is repre- sented in turtle samples taken from the Pascagoula river. Assuming the validity of the type locality, S. c. carinatus may be sympatric with S. c. peltifer, or the inferred distribution may reflect an interdigitation of the ranges. The probable distribution of S. c. peltifer is Mississippi to western Florida. The northward distribution cannot be surmised but it definitely reaches into northern Alabama. Smith and Glass (1947) allocated a specimen from Tennessee mentioned by Stejneger (1923) to this form, but did not examine it. The specimens referred to by Neill (1948) from "near the fall line" in Georgia are Sterno- therus odoratus. Neill reached and informed us of this conclusion in recent conversation, and showed us material similar to that described in his paper. Further collections from critical areas and examination of additional museum material must serve as a basis for defining the ranges of the various forms under consideration. A map showing the probable dis- tribution of the Sternotberus carinatus complex is given in figure 10. Indicated taxonomic arrangement of Sternotberus carinatus COMPLEX Sternotberus c. carinatus is distinctive by having a pronounced, acutely keeled carapace. This keel persists in old individuals, though somewhat blunted by slight arching of the carapace. The gular scute is absent. This turtle may be sympatric in part of its range with S. c. peltifer. These differences are of specific value and Sternotberus carinatus should be recognized as a distinct species. This arrangement leaves S. c. minor and S. c. peltifer in another group which would be Sternotberus minor minor and Sternotberus minor peltifer as previously suggested by Smith and Glass (1947). This is reasonable because both of these forms: ( 1 ) have the same growth progression, i. es to- ward development of a low, unkeeled and arched carapace in adults; (2) are allopatric; and (3) the most important differentiating char- acteristic of S. m. peltifer (the head and neck striping) is present in some individuals of 5". m. minor. More conclusive is the existence of a population of turtles in the Escambia river which is apparently an intergrading one between these two races. Therefore, the genus Sternotberus consists of two well-marked species, S. carinatus and S. odoratus with another complex of less cer- tain relationships made up of 5". depressus and the two races of 5". minor. This latter group of three forms is more closely related to No. 3 Tinkle and Webb: New Sternotherus 65 5". carinatus than to 5". odoratus and together with the former has been referred to as the Sternotherus carinatus complex. The senior author is continuing with a further study of the relationships in these species. A tentative key for the identification of the majority of individuals in the various forms of Sternotherus follows. Although S. odoratus has not been considered in detail in this paper, it has been included in the key for the sake of completeness. Key to Members of the Genus Sternotherus 1. Two distinct light stripes present on sides of head (if absent, head almost black) ; throat and chin barbels pre- sent; three dorsal keels (juveniles) or none; shields of carapace not overlapping; ground color of head usually dark. S. odoratus Light stripes usually absent; if present they alternate with dark stripes; barbels on chin only; number of keels variable; shields of carapace overlap; ground color of head light. 2 2. Gular absent; head with dark spots on a light background; carapace with a high, sharp median keel, sloping abruptly to marginals. S. carinatus Gular present; head with dark spots on a light background, or with dark stripes, or with a reticulated pat- tern; number of keels variable, but middorsal not as high nor as sharp as in S. carinatus; adult specimens with distinctly arched carapace with- out a sharp median keel. 3 3. Sides of head with alternating dark and light stripes or with dark stripes on a light background; middorsal keel in juveniles is distinct and moder- ately high; never more than one keel. S. m. peltifer Sides of head without dark and light stripes (rarely present and, if so, animal usually with three keels. 4 4. Head with dark spots on a light back- ground; carapace relatively high, the ratio of carapace angle to carapace height less than six in individuals greater than 20 mm in height; juve- niles with three keels; adults with at least a partially rounded carapace in cross section, not perfectly flat dorsally. S. m. minor Head with a reticulate pattern of dark lines on a light background; cara- pace low, the ratio of carapace angle to carapace height greater than six in individuals greater than 20 mm in height; no sharp middorsal keel; 66 Tulane Studies in Zoology Vol. 3 juveniles never with lateral keels; carapace of juveniles nearly circular in dorsal view; adults with a low carapace, arched at sides, but not rounded in cross section; carapace flat dorsally. S. depressus Material examined* — Numbers in parentheses indicate the total number of specimens in the series. Institutions from which material was utilized are abbreviated as follows: AU = University of Alabama; CM = Charleston Museum, Charleston, S. C; TCWC = Texas Co- operative Wildlife Collection of Texas A. & M. College; TU = Tulane University; RARI = Ross Allen Reptile Institute. Sternotherus depressus: TU 15902 (12), TU 16062 (11), TU 16631 (5), Mulberry Fork of the Black Warrior River, 9 mi. e. Jasper, Walker Co., Ala.; AU 52-1065, 8 mi. s. Carbon Hill, Walker Co., Ala. Sternotherus carinatus peltifer: TU 1504, 1513, 1515, 5859-62, Navco, Mobile Co., Ala.; TU 14668 (2), 14732, 16064, 16167, Black Warrior River, 17 mi. ssw. Tuscaloosa, Tuscaloosa Co., Ala.; TU 15634, 3.4 mi. sw. Camden, Wilcox Co., Ala.; TU 16168, Coosa River at Childersburg, Shelby Co., Ala; TU 16608, Alabama River, 4 mi. n. Whitehall, Lowndes Co, Ala.; TU 16623 (3), Black Warrior River, 3 mi. e. Eutaw, Greene Co, Ala.; TU 16634 (4), Coosa River, 6 mi. e. Pell City, Talladega Co, Ala. Sternotherus carinatus carinatus: TU 1373, 1379-80, 1385, 1395, 1408-09, 1412, 1426, 1433, 1437, 1439, 1452-54, 1456, 1460, 1470, 1472- 75, 1478-79, 1482, Jonesville, Catahoula Par, La.; TU 11303, 14010, Pearl River near Angie, Washington Par, La.; TU 11647-48, 11661 (5), 12011-12, 12038-41, 12058 (23), Pearl River, 7 mi. e. Varnado, Washington Par, La.; TU 14349, tributary of Sabine River, 9 mi. nw. Joaquin, Shelby Co, Texas; TU 14816 (10), 14925, 16545 (4), Pascagoula River, 13 mi. sw. Lucedale, George Co, Miss.; TU 16047 (2), Tensas River at Clayton, Concordia Par, La.; TCWC 511-13, Twin Lakes, Madison Co, Tex.; TCWC 521, 684, Wickson Lake, Brazos Co, Tex.; TCWC 4647, Navasota River, 6 mi. w. Normangee, Brazos Co, Tex.; TCWC 4689-90, Black Lake, 17 mi. nne. Bryan, Brazos Co, Tex.; TCWC 7236, Gatesville, Coryell Co, Tex.; TCWC 8978-79, Leon River, 5 mi. n. Hamilton, Hamilton Co, Tex. Sternotherus carinatus minor: CM 57-87-2 (2), RARI 769-79, Mc- Kinneys' Pond near Midville, Emanuel Co, Ga.; CM 54-144-12 (23), RARI 700-719; 721-731, Ichtucknee Spring run between Suwannee and Columbia Cos, Fla.; RARI 732-33, 736, 743-45, 765-68, 787, 788-90, 797-99, 804, Silver Springs, Marion Co, Fla.; RARI 734-35, 742, Silver Glen Springs, Marion Co, Fla.; RARI 737, small stream near Eureka, Marion Co, Fla.; RARI 739-41, 746-53, 754-64, 780- 85, 803, 786, 793-96, Cliipola River, 4 mi. n. Scott's Ferry, Calhoun Co, Fla.; RARI 791-92, Oklawaha River near its junction with Fla. hwy. 40, Marion Co, Fla.; TU 13313, 13342-43, 13353, 13356, 13359, No. 3 Tinkle and Webb: New Stemotherus 67 13368-69, 13411, 13422, 13574 (2), 15244, Chipola River, 4 mi. s. Marianna, Jackson Co., Fla.; TU 15629, 6.5 mi. nw. jet. hwys. 79 and 177, Holmes Co., Fla.; TU 15829 (5), 16565 (16), Escambia River, 1.2 mi. e. Century, Escambia and Santa Rosa Cos., Fla.; TU 15848 (5), Wacissa River, 1 mi. s. Wacissa, Jefferson Co, Fla.; TU 15915 (18), Suwannee River at Fannin Springs, Gilchrist Co., Fla. References Cited Cagle, Fred R. 1952. The status of the turtles Graptemys pulchra Baur and Graptemys barbouri Carr and Marchand, with notes on their natural history. Copeia, 1952 (4) : 223-234. 1953. Two new subspecies of Graptemys pseudo- geographica. Occ. Pap. Mus. Zool. Univ. Mich., No. 546: 1-17. 1954. Two new species of the genus Graptemys. Tulane Stud. Zool, 1(11): 165-186. Carr, Archie F. 1952. Handbook of Turtles. Comstock Publ. Co., Ithaca, New York. pp. 1-542. Chaney, A. H. and C. L. Smith 1950. Methods for collecting map- turtles. Copeia, 1950 (4) : 323-324. Chermock, Ralph L. 1952. A key to the amphibians and reptiles of Alabama. Geol. Surv. Ala., Mus. Pap., No. 33: 1-88. Mosimann, J. 1955. Methods for measuring cross-section and volume on turtles. Copeia, 1955 (1) : 58-61. Neill, Wilfred T. 1948. The musk turtles of Georgia. Herpeto- logica, 4(5) : 181-183. Smith, Hobart M. and Bryan P. Glass 1947. A new musk turtle from the southeastern United States. Jour. Wash. Acad. Sci., 37(1) : 22-24. Stejneger, Leonhard 1923. Rehabilitation of a hitherto overlooked species of musk turtle of the southern states. Proc. U. S. Nat. Mus. 62(6): 1-3. I'f I » 'Lew ^Ttea^sj urn ^®®il(DOT Volume 3, Number 4 September 30, 1955 A NEW CAMBARUS OF THE DIOGENES SECTION FROM NORTH LOUISIANA (Decapoda, Astacidae) GEORGE HENRY PENN, DEPARTMENT OF ZOOLOGY, TVLANE UNIVERSITY, NEW ORLEANS, LOUISIANA MUS. COM?. ZQOL LIBRARY 1 7 1955 TULANE UNIVERSITY NEW ORLEANS IULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the area bordering the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and deals with an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Horton H. Hobbs, Jr., Associate Professor of Biology, Uni- versity of Virginia, Charlottesville, Virginia. Fenner A. Chace, Jr., Curator, Division of Marine Inverte- brates, United States National Museum, Washington, DC. Austin B. Williams, Assistant Professor of Zoology, Institute of Fisheries Research, University of North Carolina, Morehead City, North Carolina. Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers may be purchased by individuals, but subscriptions are not accepted. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers to the editor. Re- mittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zool. Price for this number: $0.25. Assistants to the Editor: Carol L. Freret Donald W. Tinkle George Henry Penn, Editor, Meade Natural History Library, Tulane University, New Orleans, U. S. A. OCT 171955 HARVARD A NEW CAMBARUS OF THE DIOGENES SECTION FROM NORTH LOUISIANA (Decapoda, Astacidae) GEORGE HENRY PENN, Department of Zoology, Tulane University, New Orleans, Louisiana The Diogenes section of the genus Cambarus, to which the new species described here belongs, was defined by Ortmann (1931: 146) to include those species with an ovate, depressed cephalothorax with- out lateral spines; rostrum without lateral spines; chelae short and broad, depressed, and ovate; areola very narrow or obliterated in the middle, and always distinctly longer than half of the cephalic section of the cephalothorax. Up until now seven species and a subspecies have been assigned to this section: Cambarus dio genes diogenes Girard (1852: 88), C. diogenes ludovicianus Faxon (1884: 144), C. fodiens (Cottle, 1863: 217), C. hedgpethi Hobbs (1948: 224), C. byersi Hobbs (1941: 118), C. uhleri Faxon (1884: 116), C. carolinus (Erichson, 1846: 96), C. monongalensis Ortmann (1905: 395), and a species described but unnamed by Hobbs (1942: 168). Most of the material on which the description is based was collected in the vicinity of Ruston, Louisiana by Thomas H. Nickerson to whom I am indebted for these and other lots of crawfishes. CAMBARUS DISSITUS, sp. nov. Diagnosis. — Rostrum without lateral spines; antennal scale not ex- tending beyond tip of rostrum; areola obliterated or very narrow in middle; chelae depressed apically, palm inflated; hooks on ischiopo- dites of third and fourth pereiopods; mesial process of first pleopod of form I male grooved so as to appear twisted; central projections of the two first pleopods recurved caudomesiad so that in situ they over- lap in the mid-ventral line. Holotype male, form I. — Body ovate; abdomen narrower than cep- halothorax (10.0-12.5 mm in widest parts respectively). Width of cephalothorax (figs. 1, 2) equal to depth in region of caudodorsal margin of cervical groove (12.0-12.0 mm). Greatest width of cep- halothorax slightly caudad of caudodorsal margin of cervical groove. Areola obliterated in middle; cephalic section of cephalothorax 1.62 times as long as areola; length of areola about 38 percent of entire length of cephalothorax. Rostrum directed cephaloventrad; upper surface shallowly excavate; margins converge slightly from base and turn abruptly mesiad at base of the acumen; no lateral spines, hence acumen is not distinctly set off from the rest of the rostrum. Rostrum with a few punctations at base; apical two-thirds glabrous. Rostral ridges weakly inflated. Postorbital ridges low and terminating anteriorly without spines. Branchiostegal spines minute, blunt. 74 Tulane Studies in Zoology Vol. 3 \ II 12 Figures 1-13. Cambarus dissitus, sp. nov. : 1, 2, cephalothorax of the holotype; 3, epistome of the holotype; 4, antennal scale of the holo- type; 5, chela and carpus of the holotype; 6, hooks on the third and fourth pereiopods of the holotype; 7, 8, 9, mesial, caudal and lateral views of the first pleopod of the holotype; 10, ventral view of two first pleopods in situ on a paratype; 11, 12, mesial and lateral views of the first pleopods of the morphotype; 13, annulus ventralis of the allotype. Pubescence removed from all structures illustrated. No. 4 Penn: A New Cambarus 75 Surface of cephalothorax sparsely punctate dorsally and slightly granulate laterally. Cephalic section of telson with one spine in each caudolateral corner. Epistome (fig. 3) wider than long, terminating anteriorly in a strong median spine. Eyes normal. Antennules of usual form; a spine present on ventral side of basal segment. Antennae broken (but, not extending beyond the caudal margin of the cephalothorax in any of the other specimens examined). An- tennal scale (fig. 4) short, not reaching tip of rostrum; total length approximately one-fourth that of areola (2.5-10.5 mm); widest point distad of middle; lateral margin terminating in a strong spine. Right chela ( fig. 5 ) depressed; palm inflated; thickness of palm about 70 percent of its width (5.0-8.5 mm). Fingers curved ven- trally from their bases, gaping for entire length; fingers punctate above and below; palm punctate above, sparsely granulate below. Palm with six tubercles along mesial margin. Immovable finger with six tubercles on basal two-thirds of opposable margin; third tubercle from base of finger largest. Dactyl with five tubercles on basal two-thirds of opposable margin; middle tubercle largest. Carpus (fig. 5) longer than wide, slightly longer than mesial mar- gin of palm (7.7-6.0 mm); with a well-defined longitudinal furrow above. Mesial margin with seven tubercles irregularly arranged, the largest one at the distal end. Under side with five small tubercles near mesial margin and two larger ones at distal end. Hooks (fig. 6) present on ischiopodites of third and fourth pereio- pods. Hooks simple; length of hook on third pereiopod about one- half the greatest width of the ischiopodite; length of hook on fourth pereiopod about one-third the greatest width of the ischiopodite. Coxopodite of fourth pereiopod with a prominent, flattened, ventro- caudal longitudinal projection which meets anterior margin of coxo- podite of fifth pereiopod. First pleopod (figs. 7, 8, 9) reaching to middle of coxopodite of third pereiopod when abdomen is flexed; terminating in two dis- tinct parts. Central projection corneous and bladelike, recurved caudo- mesiad at slightly greater than a right angle to main shaft of pleopod; fusion line of its two component elements clearly marked. Mesial process grooved so as to appear twisted; not bulbous; recurved caudo- laterad at slightly more than a right angle to the main shaft of the pleopod. In situ, the central projections of the two pleopods overlap each other in the mid-ventral line (fig. 10). Mesial surface of the endopodite heavily bearded. Morphotype male, form II. — Very similar to holotype in general appearance; areola slightly open (Table 1); chelae and hooks on 76 Tulane Studies in Zoology Vol- 3 TABLE 1. Measurements (in millimeters) of Cambarus diss; itus Types Holotype $ I Allotype 5 Morphotype $ II Cephalothorax Length Width (greatest) Depth (greatest) 27.5 12.5 12.0 29.0 14.0 12.0 25.5 11.5 11.0 Areola Length Width (at narrowest part) 10.5 0.0 11.0 0.1 9.5 0.2 Rostrum Length Width at base 4.7 3.8 4.5 3.7 4.2 3.7 Antennal scale Length Width (greatest) 2.5 1.0 2.2 1.1 2.5 1.0 Epistome Length Width 1.1 2.4 1.4 2.6 1.1 2.3 Abdomen Length (including telson) 24.0 28.0 23.0 Chela Length of outer margin 17.0 Length of dactyl 11.5 Width of palm 8.5 Thickness of palm (greatest) 5.0 15.0 10.0 7.6 4.5 14.0* 9.0 6.5 4.0 * left chela measured on morphotype ; right chela on other types. ischiopodites of third and fourth pereiopods reduced. First pair of pleopods (figs. 11, 12) reaching to caudal margin of coxopodites of rhird pereiopods when abdomen is flexed; all processes reduced and non-corneous. Allotype female— -Very similar to holotype in general appearance; areola slightly open (Table 1); chelae reduced. Caudoventral pro- jections on coxopodites of fourth pereiopods undeveloped. Annulus ventralis (fig. 13) immovable, about 2.25 times wider than long; with a rounded depression on the anterior face, behind and ventral to which there is an irregular antero-ventrally projecting transverse ridge. The whole effect in ventral aspect resembles somewhat a baseball catcher's mitt standing on edge. The sinus originates in the right side of the anterior depression, runs ventrally and dextrad to the apex of the posterior ridge, then turns sinistrad to the midline on the posterior face of the annulus and terminates near the base. The sternites of the fourth and fifth thoracic segments are smooth and do not encroach on the annulus. Type locality. — The holotype was dug from a shallow burrow near a stream three miles east of Choudrant, Lincoln Parish, Louisiana, on February 24, 1952 by T H. Nickerson. The allotype and morpho- No. 4 Penn: A New Cambarus 11 type were dug from similar burrows two miles east of Choudrant on the same day. No other species of crawfishes was found at either locality. Disposition of types. — The holotype, allotype and morphotype are deposited in the United States National Museum, numbers 98125, 98126, and 98127 respectively. The 31 paratypes are in the follow- ing collections: Academy of Natural Sciences of Philadelphia, Ameri- can Museum of Natural History, Carnegie Museum, personal collec- tion of Dr. Horton H. Hobbs, Jr. at the University of Virginia, and Tulane University. Geographic distribution. — The type series of Cambarus dissitus were collected from four localities in northern Louisiana. These records and a summary of deposition of specimens are as follows: Caldwell Parish: 2 $ S I, Kelly, December 24, 1953, W. E. Shell (TU 2998); Lincoln Parish: 2^1, three miles east of Choudrant, February 24, 1952, T. T. Nickerson (USNM 98125, TU 3124); 1 $ I, 2 $ $ II, 2 2 9,1 $ juv., 2 5? juv., two miles east of Choudrant, February 24, 1952, T. H. Nickerson (USNM 98126 and 98127, TU 3123); 12 $ $ I, 7 ? 2, 3 5$ juv, Ruston, May 17, 1953, T. H. Nickerson (ANS, AMNH 11756, CM, HHH, USNM 98128, TU 3125). Ecological and life history notes. — All collections have come from the upland shortleaf and longleaf pine hills of the State. The soils of this area are for the most part sand and sandy clay (longleaf pine hills) or sandy clay and silt of non-alluvial character (shortleaf pine hills) both of which are usually well drained and fairly dry (Viosca, 1933). All of the specimens were dug from shallow burrows, two along a stream, two in a hillside seepage area, the remainder in areas considerably farther removed from surface water. Form I males were taken in February, May and December, mature females only in February and May. The smallest juvenile, a female with an 18.0 mm cephalothorax, was taken in May. The absence of smaller juveniles from all collections of C. dissitus is suggestive of an aquatic habitat for the immature stages, as in other species of the section, but it may represent merely the bias of the collectors. Variation. — Body ratios from four samples (17 specimens) of form I males (Table 2) and two samples (8 specimens) of mature females (Table 3) show the greatest variability in the length of the rostrum, length of the antennal scale, and width of the areola. Although the rostrum, expressed as a proportion of cephalothoracic length, shows considerable variation in length, the length-width proportions are relatively constant in both males and females. The same appears to hold true for the antennal scale in relation to cephalothoracic length and in length-width ratios. In all except two specimens (TU 2998) the antennal scale was notably short and did not extend anteriorly to the tip of the rostrum. The only other species of the section with such a short antennal scale is Cambarus byersi. The areola is obliterated in the middle in twenty (58.8 percent) 78 Tidane Studies in Zoology Vol. 3 &i > T3 lo bo oj Cxi r-t CO o "xf (M CO -1 00 o Cxi CO CO o lo 00 o Tf o OS LO OS OSi-H ©CD N 1—1 1—1 SO Cxi i-i co iH t- NHO NH OS 5 Cg lo Cxi 00 o OS t- t- CD OS os 1"H o lo o-<* OO LO 00 CD O OOS -xf CD Cxi CO "5* © cxi o eg LO oo LO* Cxi LO LO CD LO CO Cxi i-l CO OS os co co "xf co" t- o tH LO i-" 00 o o o CD Cxi tH O Ox«0 o LO CO CO o Cxi !-" © lo o ©■<# ■<* o O ©-xf © cxi r-i © o os Cxi i ooo < oo OS OS p cu bD ss o3 P3 LO iH co O LO iH Cxi os •xf t- ■xf LO •■xf os t- O "xf ■xf CO-* o LO CO LO LO LOCO OLO Cxi tH LO Cx] tH CO Cxi HO t- LO Cxi N o cu "sj LO fc Cxi 03 00 P os Cxi o co o os Cxi CD CD Cxi CD CD LO t-OOi-t o ■xf ©"xf O CO t- OCO LO LO Cxi Cxi o Cxi CD Cxi o o oo o os co Cxi i-H Cxi I -x* o "xf Cxi Cxi o Cx] o Cxi Cxl LO LO CO ■xf CO 00 c- co' LO ■xf os o CD os co o Cxi Cxi iH OLO os O CO CO o LO tH Tf O cxi tH oo o iH I I I I ■xf co oso rf oco o * * CO t- oco co Cxi co CD Cxi HO o OS LO Cxi o Cxi o o LO 00 Cxi co Cxi CD tr- ee *xf o o 00 Ox*co LOCxl xtf ++ ooo O-xf CXI i-H LO Cxi CO CO Cxi iH o Cxi' X o3 tH o Xi .. ■+-> x"2 2£ ' o 03 CJ "ol « X 8-* o ft o c cs fl ,2 -So o3 f3 X cu ftp o a bo rC a) cu o ,2 bo ,fi cy O 3 »J3 X w uS O x5-T £^ cu O -^ .. efl o 03 S3 C ai XQJXi)X™X+f cS?HC«-«c3.Sc8ft Sh=! •rH hT jJ ^ ^ CU H "hn ^JS o x-Sxi oQ o tb o "Sd^ bfi° id (« C cS fl oi fi 03^2 " X a>x a>^5 4jj3>C'« ft^ ftp ftp ft^ « cu a> a> cu * o o u o K c 03 < u 03 ^= i-H -M ed bOfi c a ai a) J CJ CD 3 O ,J3 O CJ ^g l-H S3 u 0) a> ^D s ft CC iH o SO r/7 iii CU 0) £H Q O PQ 6C > < T3 03 O O 03 ! bO ! s oS oc C5 00 iH tP LC) 00 i-l i-l Ttf t- CO CD Ci HMlOt-fflONNH^t+HlOW NHtOC4HHt>NHd oirHr-i OMHrnooOHH^Nioo^ot- H N M t> N N H 00 N H O O N H H 00 i— I rH I I I I I I I I I I Ml I I C0^f*00t>O(N(MNOOt>a5C0 ioom'oioooot-roOTiioo)'*«o ffl N O U3 N H H in eg co P H X 03 03 bo C c3 OOI>OOJNNOOOC!iM ©©COjTHed0OCNJr-Ir-5 THeO^CStOI^OOt-N^tO-^fMCn OlMi-i03i-iHO]NinOHU5(0 i i i i i i i i i i i 7 i i i NOTf^OOOOMOOONOC inOfficotoffiooooHijiiooiifltD dNdioNHHdNi-idi>rtrti-! (M T-I ^ o 03 ft t+-l o 03 X IS i5 03 t as o c S ! 03 £ c o ^Q -(-> -l-> X bo bo-£ 03 03 kT g12 — ' ^X as X -»j 2 S^ < X X & as O o XX X X as as o o XX OS G$ 03 M M ?H o o o XXX -- -t-> 03 bo c U 03 O O o o o o o as a XX ft ft 03 03 ft ft 03 03 d & & ft ft ft 03 03 03 ooo X l>©2 a » g g as +j w 03 C O 03 s o X 5 Eh x "J s sCfl "x _C !> as as +j 03 bO+3+3^ J c bo bo S 0)hJ 03 03 03 g .. JhJPh O as -i_) ^ ^ & & .2 (u'oJ'S'qJ ft MXXX h<:ooo p H -a c T3 CQ 03 as a i— 1 a U a as V § 03 bfl o o aS •v N h a i-i > z C5 ci § S o C <: 2 • «« r/l P -a 03 as < , t M •« 03 03 s efl P-H fe ^H ^l rr; T3 o a t— H Bt o ^H X O 03 O c M w as c 0} o aj X "is 0 o ■13 h 1— 1 ai o C . ,nH +J • i o 03 u+ P5 ft as 03 iH en oa r/l 03 13 03 73 'S T3 fl S 3 U o CJ C c C * ++ 80 Tulane Studies in Zoology Vol. 3 of the specimens examined, but there is considerable variation with respect to sex and age, e. gv obliterated in 64.7 percent of form I males, 33.3 percent of mature females, 50.0 percent of form II males, and 83-3 percent of the juveniles. However, where the areola is open it is only slightly so and is never less than 35 times longer than its narrowest width. Relationships. — With the exception of having hooks on the ischi- opodites of its third and fourth pereiopods as opposed to hooks on only the third pereiopods of other species in the Diogenes section, Cambarus dissitus appears to be more closely related to C. fodiens, hedgpethi and byersi than any others. The twisted appearance of the mesial process of the first pleopod of form I males and general bodily proportions place it nearest to hedgpethi. The first pleopods of Cambarus dissitus show a superficial similarity in structure to those of Procambarus tenuis Hobbs (1950: 194). In P. tenuis the cephalic process is reduced and inconspicuous and the caudal element is lacking, leaving the central projection and the mesial process as the most conspicuous parts. These are produced in a man- ner very similar to those of the genus Cambarus in general, but re- semble the arrangement in C. dissitus most closely in the midventrally crossed-over central projections. Thus, P. tenuis, a disjunct member of the Blandingii section of Procambarus, and C. dissitus perhaps show a closer approach in pleopod structure than any other two species of their respective genera. Only two other crawfishes are known with crossed-over pleopods: Orconectes clypeatus (Hay, 1899: 122) and 0. beyeri Penn (1950: 166). Derivation of name. — The species name is derived from the Latin word dissitus, meaning "lying apart", in allusion to the unique posi- tion of the species in the Diogenes section. References Cited Cottle, T. J. 1863. On the two species of Astacus found in upper Canada. Canad. Jour. Industry, Sci. & Arts, (n.s.) 8: 216-219. Erichson, W. F. 1846. Uebersicht der Arten der Gattung Astacus. Archiv. f. Naturgeschichte, 12 (1) : 86-103. Faxon, Walter 1884. Description of new species of Cambarus; to which is added a synonymical list of the known species of Cam- barus and Astacus. Proc. Amer. Acad. Arts & Sci., 20: 107-158. Girard, Charles 1852. A revision of the North American Astaci, with observations on their habits and geographical distribution. Proc. Acad. Nat. Sci. Phila., 6: 87-91. Hay, W. P. 1899. Description of two new species of crayfish. Proc. U.S. Nat. Mus., 22: 121-123. Hobbs, Horton H., Jr. 1941. Three new Florida crayfishes of the subgenus Cambarus. Amer. Midi. Nat., 26 (1) : 110-121. 1942. The crayfishes of Florida. Univ. Fla. Publ, Biol. Sci. Ser., 3 (2) : 1-179. . 1948. A new crayfish of the genus Cambarus from No. 4 Venn: A New Cambarus 81 Texas, with notes on the distribution of Cambarus fodiens (Cottle). Proc. U. S. Nat. Mus., 98: 223-231. 1950. A new crayfish of the genus Procambarus from Oklahoma and Arkansas. Jour. Wash. Acad. Sci., 40 (6) : 194-198. Ortmann, A. E. 1905. The crawfishes of western Pennsylvania. Ann. Carnegie Mus., 3 (2) : 387-406. 1931. Crawfishes of the southern Appalachians and the Cumberland plateau. Ibid., 20 (2) : 61-160. Penn, George Henry 1950. A new crawfish of the genus Orconectes from Louisiana. Jour. Wash. Acad. Sci., 40 (5) : 166-169. Viosca, Percy, Jr. 1933. Louisiana Out-of-Doors, A Handbook and Guide. New Orleans, publ. by author, pp. 1-187. I v-' i urn Volume 3, Number 5 December 28, 1955 NOTROPIS EURYZONUS, A NEW CYPRINID FISH FROM THE CHATTAHOOCHEE RIVER SYSTEM OF GEORGIA AND ALABAMA ROYAL D. SUTTKUS, DEPARTMENT OF ZOOLOGY, TV LANE UNIVERSITY, NEW ORLEANS, LOUISIANA 1Y .ii JAN 1 3 (956 TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and con- tains an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Edward G Raney, Professor of Zoology, Cornell University, Ithaca, New York FRANK B. CROSS, Assistant Professor of Zoology, University of Kansas, Lawrence, Kansas Donald C. Scott, Assistant Professor of Zoology, University of Georgia, Athens, Georgia Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers or volumes may be purchased by individuals, but subscriptions are not accepted. Lists of papers published will be mailed on request. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers or volumes to the editor. Remittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zooh Price for this number: $0.50. George Henry Penn, Editor Meade Natural History Library, Tulane University, New Orleans, U. S. A. Assistants to the Editor: Miriam Hale Don R. Boyer JAN 1 3 1956 NOTROPIS EURYZONUS, A NEW CYPRINID FISH FROM THE CHATTAHOOCHEE RIVER SYSTEM OF GEORGIA AND ALABAMA1 ROYAL D. SUTTKUS, Department of Zoology, Tulane University, New Orleans, Louisiana The species here described is a colorful minnow which apparently occurs only in the tributaries of the lower part of the Chattahoochee River. The author wishes to thank the following persons who aided in the collection of specimens or loaned specimens under their care: Richard H. Backus, Reeve M. Bailey, Charles F. Cole, Robert H. Gibbs, F. E. Guyton, Charles D. Hancock, L. James Kezer, Edward C. Raney, and C. Richard Robins. Additional thanks are due Edward C. Raney for his encouragement and interest shown throughout the initial study done by the writer while a graduate student. NOTROPIS EURYZONUS, sp. nov. Figs. 1, 2, Map 1 Materials. — The type material consists of 163 specimens from 21 to 53 mm in standard length taken at eight localities in Uchee Creek, a tributary to the Chattahoochee River. Other material examined con- sists of 301 specimens, 21 to 55 mm, from 11 localities in other tributaries of the Chattahoochee River. Below in parentheses are indicated the number of specimens and the range of standard length in millimeters, e.g. (5, 25-42). In addition to standard abbreviations for compass directions, with the following "of" deleted, the following are used: Co. = County, Cr. =: Creek, mi. = mile or miles, R. = River, trib. = tributary (of), Hwy. = Highway, CU = Cornell Uni- versity, TU = Tulane University, UMMZ = University of Michigan, Museum of Zoology. Holotype, CU 28346, an adult male, 49 mm in standard length, from Uchee Cr., trib. Chattahoochee R., 0.7 mi. E. Marvyn, Lee Co., Alabama, on June 12, 1949, by Royal D. Suttkus, Robert H. Gibbs, and Charles F. Cole. Thirty-six paratypes, CU 15990 (28-47), bear the same data as the holotype. Other paratypes, listed below, are all from Uchee Creek, Alabama: CU 13983 (5, 25-42), trib. Uchee Cr., 3.1 mi. E. Marvyn, Hwy. 80, Russell Co, March 24, 1948; UMMZ 123951 (1, 37), Uchee Cr. at Marvyn, August 4, 1937; UMMZ 128744 (6, 22-38), Brush Cr, trib. Uchee Cr, Russell Co, May 10, 1939; UMMZ 128745 (1, 37), Brush Cr, trib. Uchee Cr, Russell Co, May 10, 1939; CU 16194 (2, 34-36), 1 This paper is based in part on a manuscript submitted as a par- tial fulfillment of a doctoral dissertation at Cornell University, Ithaca, New York. The study was aided in part by a loan from the Revolving Research Fund of the Society of Ichthyologists and Herpetologists, and in part by a grant from the University Council on Research at Tulane University. 86 Tulane Studies in Zoology Vol. 3 Uchee Cr., 9-2 mi. S. Phoenix City, Russell Co., June 12, 1949; CU 14316 (43, 21-53), Little Uchee Cr., 0.9 mi. E. Crawford, Hwy. 80, Russell Co., March 24, 1948; TU 10700 (8, 32-47), trib. Little Uchee Cr., 1.1 mi. E. Crawford, Hwy. 80, Russell Co., September 17, 1955; TU 10718 (60, 22-53), trib. Uchee Cr, 3.2 mi. W. Crawford, Hwy. 80, Russell Co, September 17, 1955. Other material examined from tributaries of the Chattahoochee R. is listed below by state. Alabama: CU 15826 (5, 35-50), Hatche- chubbee Cr, 4 mi. S.W. Seale, Russell Co, June 12, 1949; CU 17491 (18, 33-55), Owens Branch, trib. Abbie Cr, 1.2 mi. E. Abbieville, Hwy. 10, Henry Co, March 28, 1950; CU 17760 (44, 23-46), trib. Abbie Cr, 2.6 mi. S. Abbieville, Hwy. 241, Henry Co, March 28, 1950; CU 17665 (25, 26-43), Omussee Cr, 5.8 mi. N.E. Dothan, Hwy. 241, Houston Co, March 28, 1950; CU 16108 (68, 21-49), trib. 9-8 mi. S.W. Eufaula, Barbour Co, June 13, 1949; TU 2564 (66, 21-50), trib. 3-9 mi. N. Columbia, Hwy. 95, Henry Co, June 1, 1951; TU 2550 (27, 26-43), trib. 6.5 mi. N. Gordon, Hwy. 95, May 31, 1951. Georgia: CU 17455 (16, 27-53), Hodchodkee Cr, 1.1 mi. E. Lumpkin, Hwy. 27, Stewart Co, March 28, 1950; CU 15878 (8, 24-54), Hodchodkee Cr, 1.4 mi. S. Lumpkin, Hwy. 27, Stewart Co, June 11, 1949; CU 17773 (9, 26-53), Hannahatchee Cr, 8.1 mi. N. Lumpkin, Hwy. 27, Stewart Co, March 28, 1950; CU 17157 (14, 26-47), Hichitee Cr, 4.1 mi. S. Cusseta, Chattahoochee Co, March 28, 1950; CU 15813 (1, 43), Upatoi Cr, 6.7 mi. S. Talbotton, Hwy. 80, Talbot Co, June 11, 1949; TU 7649 (14, 26-40), Upatoi Cr, 6.7 mi. S. Talbotton, Hwy. 80, Talbot Co, October 11, 1953. Methods. — Counts and measurements were made following the methods described by Hubbs and Lagler (1947: 8-15), except for those listed below. 1. Dorsal to opercle count; the number of scale rows crossing a diag- onal between the origin of the dorsal fin and the first lateral line scale at the margin of the opercle. Single isolated scales along the diagonal, were not included. 2. Dorsal fin, origin to tip of posterior lobe or last ray; when the posterior lobe was not developed the tip of the longest element of the last (split) ray was used. 3. Anal fin, origin to tip of posterior lobe or last ray; the procedure was the same as described for number 2 above. Diagnosis. — A species of Notropis with 2, 4 — 4, 2 teeth and anal rays modally 10, often 9 or 11, rarely 8 or 12. Other fin rays: dorsal 8, sometimes 7, occasionally 9; pectoral 13 to 16, rarely 12 or 17; pelvic 8, rarely 7; caudal 19, occasionally 18. Scales: dorsal to opercle rows 17 to 22, rarely 16 or 23; lateral line scales 35 to 40, rarely 34, 41 or 42; around the body before dorsal fin 27 to 30, occasionally 26, 31 or 32, rarely 25 or 34; around caudal peduncle 12 or 13, occasion- ally 14 or 15, rarely 16. Body very deep and compressed. Origin of dorsal fin closer to base of caudal than to tip of snout and farther No. 5 Suttkus: A New Cyprinid Fish 87 CO O 0> US'-1 Ut-, esP QJ«D ft"* •+J 00 Wo a LO o> ^TH^CKMooos-^ost-eoo^ossCi-iiHioootMOj-^ieotciooooeooifMt-co (—} eo (V~t l~^ i-T\ I-*- rf\ r^\ rs\ f* \ r—i r—i **M t~-m r^\ r~r\ ***m *n-i rr\ r*~\ \t-\ ai rr\ *r\ \^. /^i /^s rY\ r>™ • ■ ■ ^— v. ^ •*** w* ^j- w» ».- ••■»/ w» ^<- ■•** i — i i — i *w v^j ^nj >^v vi' v*> \^ v^j vjw (,'j gj un| *-~ «•'•! 0?DOOC>C5t-OOCOOOO'-IOTft-C005C-eOC£)OOU3(Mi©«£)ini(N0500t> HHOONOONONNNNNHH "#lOTt«COTj«eOIMCONOI>M«OMOO)l»l»t-T-II>i-l'<#>nMMTjOHOMOOlNHH(»t-OCSO TflOlOM^OJNHNONHIMHHOOOlOONOCCMNNMHM ^HOffit-OJOMOOOTliOJlOlOCOMacOMKKOOOOOttiMtDlOW tOtDHt-OOOOOOHOINHiJit-MOt-OtOQOmONIMaoOOOiO ■^lOlOM^COMHNOINHNHHHOeOOONOMCOIMNCOHN III I I I I I I I I I I I I I I I I I I I I I I I e0OTt<0i-^,'^00C£>00«0 00O00 00t>O00<>]00 00 00C0ir3C0O :^00Wt-t-MN0500OHC05DNCSt>t>«D00tDC a co 0) Ot»O00O000i^05OIMHiOt»C0OMKIt»00t-(N0000t-«)O0)M MIOMNHHHNHcgHHHOINOONOlNIMINNMHH bjo-^icmeoiocoiM' I I I I I I I III III I I I I "I" I I I I IT 1' "I HIXNHHOSOOHHroiOfOlt-OONlOOt-HCOlOmNMNMOlO • ri*i l-— eo r^ CO l->- /-w r*-i *-rs i— 4 <—i m eo rvi f-r\ i-— fvi pft iv\ *-h ^i »/^ */-\ ~* ^i r^\ nrt rr* i-li-ig)0ur-lr-(roi«'^'roL"-QUIM10OC"r-IP3mCgCQKINCgO'« M^CONHHONHNHHOOIMOONOOJNIMNNHH ■^ ^C0(NW0i(^C0ili5OC0tr-00t-TjHHC0t0N0>t-0i«D0000 3 ft±5 • o a! o-tJ'H £, yXl fe o s ~ o bo 01 • l-H co o> co o ft o ft5 "■PS 9, w. 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O -^ rj< CO t- «D OSCOOOirSlOOOiOOOOOOOO LO rj< ^H lO ^ i-l iH 03 00 M s riU ■ u -i-j a> P 5 o (V p p ffi M ffi cg K — M w w •C S"C GO s o oo 03 fa > « fa fa W O o o H <: H H o o fa Z fa *-■ E-i fa ^ 3" W fa faH m « Hgo3 go fa H o W ^^ o £ ec w K a « £ M fa 5 W 03 w fa 5 co eo co coco o s S5 NMt-t-O (M r-l COC•£; ^S a^ * ^ s.s . ~ CD W M ?> c3 fl 5>5 2 !• .;!? 03 _ © 98 Tulane Studies in Zoology Vol. 3 margin of the opercle (Table 3), and a higher circumferential pe- duncle scale count (Table 4). The specimens from Hannahatchee Cr. have a low anal ray count as shown in Table 8 and are like the Uchee Creek specimens in this respect but have a higher pectoral ray count and thus were not included with the latter. Relationships. — Notropis euryzonus is most closely related to No- tropis hypselopterus (Gunther) and Notropis stonei Fowler and less so to Notropis signipinnis Bailey and Suttkus. N. euryzonus has not been taken together with either N. hypselopterus or N. signipinnis both of which occur in the same drainage. In 1951, the writer and Charles D. Hancock collected N. hypselopterus in a tributary of Chattahoochee River only two miles distant from a population of N. euryzonus. There were no apparent differences between the two streams with regards to habitats. Additional collecting may reveal cohabitation of a stream by the two forms. Notropis euryzonus is apparently an endemic of the Apalachicola River system as is Notropis hypsilepis Suttkus and Raney. The most southern locality given for N. hypsilepis by Suttkus and Raney (1955: 162) was Hodchodkee Creek, 1.4 mi. S. Lumpkin, Georgia. N. euryzonus was taken from this same locality on a different date by the author. The two species have been taken from other streams in the area of overlap which extends from Hodchodkee Creek to Uchee and Upatoi Creek. In many respects, including meristic characters, N. euryzonus is similar to N. hypselopterus, but prominent differentiating characters exist in the shape and pigmentation of the dorsal fin of the male. Figures 2-4 illustrate the shape and pigmentation of dorsal and anal fins of N. euryzonus (Chattahoochee River system), N. hypselopterus (Choctawhatchee River drainage) and N. hypselopterus (Flint River system). The general outline of the dorsal fin of N. euryzonus is rectangular and that of N. hypselopterus is triangular. The posterior elements are greatly extended in N. hypselopterus, especially so in the Flint and lower Apalachicola River specimens (males). N. hypselopterus in the Choctawhatchee River drainage has the fins and posterior part of the body colored with brilliant orange. The burnt orange color and the heavy concentration of melanophores in the dorsal and anal fins of N. euryzonus cause the fins to appear less brilliant or gaudy than in N. hypselopterus of the Choctawhatchee. N, hypselopterus in the Apalachicola drainage lack the brilliant orange but have instead some rose and dull red-orange areas on the posterior fins and body. The lateral band of N. euryzonus is gray with a tinge of blue. The clear "window" found in the caudal fin of N. euryzonus is not present in the forms of hypselopterus. Notropis euryzonus most likely evolved from a hypselopterus stock which moved up the Apalachicola River system during Pleistocene time. Possibly the Flint and Choctawhatchee River system were popu- No. 5 Suttkus: A New Cyprinid Fish 99 Map 1. Distribution of Notropis euryzonns. Circle indicates type locality. 100 Tulane Studies in Zoology Vol. 3 lated later than the Chattahoochee part of the Apalachiocola or if all three (Chattahoochee, Choctawhatchee and Flint) were populated at the same time speciation was not as rapid in the latter two streams because the forms in these systems have not reached a specific level of differentiation. Isolation was probably effected by one of the periods of coastal inundations during the Pleistocene. Ecology. — The type locality, Uchee Creek, is a shallow stream about 10 feet wide with a sand bottom. The water was brown and clear on June 12, 1949. The estimated flow was eight cubic feet per second. Most streams in which N. euryzonus was seined have colorless water. The tributaries of Uchee Cr. and the tributary of the Chatta- hoochee River, 9.8 mi. S.W. Eufaula, Barbour Co., Alabama, have brown water. The tributaries of the Chattahoochee River from which N. euryzonus was collected have various bottom types. Hodchodkee Cr., Stewart Co., Georgia has mud and clay; Abbie Cr., Henry Co., Alabama, Omussee Cr., Houston Co., Alabama, and Hichitee Cr., Chattahoochee Co., Georgia have shifting sand and silt and Hatchechubbee Cr. and one tributary of Uchee Cr., Russell Co., Alabama have exposed bed- rock and drifting sand. The specimens of N, euryzonus usually were taken near shelter either in the form of logs or aquatic vegetation. These minnows seldom moved from their niche and could be seined with little dif- ficulty. The collecting of this species was difficult only when the shelter was thick and entangled with debris. Orontium aquaticum and Sparganium sp. were the most common aquatic plants recorded for the collection localities. The incidence of Notropis euryzonus with golden club, Orontium aquaticum, was not as consistent as that noted by Bailey and Suttkus (1952: 14) for Notropis signipinnis. The name euryzonus, derived from eury, broad, and zona, zone, refers to the broad lateral band. Notropis is treated as masculine and the adjectival form is used in the formation of the specific name. References Cited Bailey, Reeve M. and Royal D. Suttkus 1952. Notropis signipinnis, a new cyprinid fish from southeastern United States. Occ. Pap. Mus. Zool. Univ. Mich., No. 542: 1-15. Hubbs, Carl L. and Karl F. Lagler 1947 (and 2nd printing, 1949). Fishes of the Great Lakes Region. Bull. Cranbrook Instit. Sci., 26 : I-XI, 1-186, many figs. Suttkus, Royal D. and Edward C. Raney 1955. Notropis hypsilepis, a new cyprinid fish from the Apalachicola River system of Georgia and Alabama. Tulane Stud. Zool. 2(7): 159-170, 2 figs., 1 map. i\j rr~ i^ nm g@@iL(D(a^ Volume 3, Number 6 December 28, 1955 FACTORS INFLUENCING THE RATE OF OXYGEN CONSUMPTION OF THE DWARF CRAWFISH, CAMBARELLUS SHUFELDT1I (Decapoda, Astacidae) MILTON FINGERMAN, DEPARTMENT OF ZOOLOGY, NEWCOMB COLLEGE, TULANE UNIVERSITY, NEW ORLEANS, LOUISIANA JAM * Q *nc$ TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and con- tains an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Frank A. Brown, Jr., Professor of Zoology, Northwestern University, Evanston, Illinois Theodore H. Bullock, Associate Professor of Zoology, Uni- versity of California, Los Angeles, California John H. Welsh, Associate Professor of Zoology, Harvard Uni- versity, Cambridge, Massachusetts Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers or volumes may be purchased by individuals, but subscriptions are not accepted. Lists of papers published will be mailed on request. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers or volumes to the editor. Remittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: "Tulane Stud. ZooL Price for this number: $0.35. George Henry Penn, Editor Meade Natural History Library, Tulane University, New Orleans, U. S. A. Assistants to the Editor: Miriam Hale Don R. Boyer JAW f 3 fo^ iiinui H "^ FACTORS INFLUENCING THE RATE OF OXYGEN CONSUMPTION OF THE DWARF CRAWFISH, CAMBARELLUS SHUFELDTII * (Decapoda, Astacidae) MILTON FINGERMAN, Department of Zoology, New comb College, Tulane University, New Orleans, Louisiana The comparative physiology of respiration has been reviewed re- cently by Zeuthen (1955). Sex, weight, endocrines, and a daily rhythmicity are among several factors which may influence the rate of oxygen consumption of an arthropod. Edwards (1946) demonstrated that the male imago of the house- fly, Musca domestica, had a higher rate of metabolism than the adult female. The higher rate of the male was due to the sexual difference and not to a weight difference. In 1950 Edwards found no sexual difference in the metabolic rate of the fiddler crab Uca pugilator. In general, within a single species on a unit weight basis small animals have a higher rate of oxygen consumption than large animals. Edwards (1946) found that this relationship held for the mole crab, Emerita talpoida, and the amphipod Talorchestia megalopthalma. The role that endocrines play in the control of the metabolic rate of crustaceans has been investigated by several workers. Scudamore (1947) demonstrated that removal of the sinus glands from within the eyestalks of the crawfish Orconectes immunis led to an increase in the rate of oxygen consumption. Sinus gland extracts decreased the rate of oxygen consumption and central-nervous-tissue extracts increased the rate. Bauchau (1948) observed that the increase in the metabolic rate of the crab Eriocheir sinensis with a rise in tem- perature was greater following eyestalk removal. He concluded that the sinus glands of this poikilotherm normally operate in the control of metabolic rate as a partial temperature compensator. Edwards (1950), working with Uca pugilator, and Bliss (1953), working with the land crab Gecarcinus lateralis, showed an increase in the metabolic rate following eyestalk removal. Scheer and Scheer (1954) showed that ablation of the eyestalks from the prawn Leander serratus is not followed by a rise in the rate of oxygen consumption. Leander was the first crustacean investigated for which no change in metabolic rate following eyestalk removal has been reported. Edwards (1950) demonstrated a daily rhythm of oxygen consump- tion in the fiddler crab Uca pugilator. This 24 hour cycle of oxygen consumption corresponded to the daily activity rhythm of the species. More recently, Brown, Bennett, and Webb (1954) confirmed the daily rhythm of oxygen consumption in normal Uca pugilator. The rate is maximal at 6-8 a.m., minimal about noon and midnight; and, 1 This investigation was supported by Grant No. B838 from the National Institutes of Health. 104 Tulane Studies in Zoology Vol. 3 a secondary maximum occurs about 10-11 p.m. The latter investi- gators also described a daily rhythm of the rate of oxygen consumption in eyestalkless individuals of this species. The daily form of the latter rhythm differed slightly from the rhythm of normal animals. The current investigation was initiated to determine ( 1 ) the effect of eyestalk removal upon the rate of oxygen consumption of the dwarf crawfish, Cambarellus shafeldtii, (2) the influence of sex and size upon the rate of oxygen consumption, and (3) the rate of oxygen consumption throughout a 24 hour period. Materials and Methods Adult specimens of the dwarf crawfish, Cambarellus shufeldtii (Faxon), identified by Dr. George H. Penn, were collected in the vicinity of New Orleans, Louisiana, for use in the experiments. The total length of these crawfish is 15 to 25 mm, the female being larger than the male. This species, whose physiology has not been investi- gated previously, is one of the more common crawfish in this vicinity. The rate of oxygen consumption of the crawfish was measured by means of ( 1 ) a continuously recording respirometer designed by Brown (1954) and (2) a Warburg respirometer. The former in- strument was used for measuring the metabolic rate over 24 hour periods, the latter for intervals up to three and a half hours. The respirometer designed by Brown consists of a collapsible plastic bag attached to 100 ml Soxhlet flask via a capillary connection. The plastic bag contained sufficient oxygen for at least 72 hours. Weights were affixed to the exterior of the flask so that the respirometer would sink just below the surface of the water in a constant tem- perature bath maintained at 29 °C. As oxygen was consumed by an animal in the flask the specific gravity of the respirometer increased and the buoyancy decreased. The respirometer, therefore, sank deeper. Increase in specific gravity was recorded by means of a lever system attached to ink pens recording on a drum moving at the rate of 0.29 cm per hour. The decrease of the oxygen volume in the respirometer caused the observational pen to trace a line which continuously ap- proached closer to a fixed base line. The respirometer increased one gram in weight for every milliliter of oxygen consumed. Therefore, the lever system could be calibrated and the volume of oxygen con- sumed per hour calculated. Data for three hour intervals were lumped. The method of analysis and presentation of the data was the same as described in detail by Brown, Bennett, and Webb ( 1954). For each determination the following were placed into each of eight flasks: a vial of 20 percent potassium hydroxide (carbon diox- ide absorbent), a vial of saturated cupric sulfate (ammonia absorb- ent), and a volume of aerated tap water sufficient to allow the craw- fish to swim. Seven of the respirometers had one crawfish in each of them, the eighth served as a control. Throughout the periods of observation only one-third of the records for the 24 hour periods could be used because the animals in some of the flasks died and No. 6 Fingerman: Oxygen Consumption of Cambarellus 105 some of the pens did not record between midnight and 6 a.m. The respirometers were maintained in a laboratory in which the blinds were drawn. The light intensity of the surface of the water in the bath never exceeded two ft.-c. The small changes in light intensity could not have accounted for the results to be described because the changes in light intensity that occurred in the laboratory were ar- rhythmic. On several evenings the laboratory lights were on until midnight with no apparent effect upon the results. The Warburg respirometer was used in the conventional manner. Each flask contained 20 percent potassium hydroxide (carbon diox- ide absorbent) and a filter paper wick in the center well, 50 percent sulphuric acid (ammonia absorbent) in the side-arm, and one ml of aerated tap water plus a crawfish. The water bath was maintained at 28.5 °C. Following removal from either respirometer, each crawfish was weighed and sexed. Total wet weight was determined by blotting each crawfish in paper towelling to remove as much of the external liquid as possible and weighing the animal to the nearest one-hun- dredth of a gram by means of a chainomatic analytical balance. The rates of oxygen consumption were expressed as milliliters of oxygen consumed per gram of tissue per hour (ml/g/hr). Statistical analysis of the data which established (1) the nature of the daily rhythm and (2) the effect of eyestalk extracts on the meta- bolic rate was not necessary because the metabolic rates of individual crawfish were not compared with one another, but each crawfish served as its own control. Individual crawfish were considered over 24 hour intervals. Individual variation influenced only the amplitude of the daily rhythm curve but not the shape of the curve, i.e. the char- acter of the daily rhythm, which was the primary object under in- vestigation. The character of the daily rhythm was the same in all the crawfish, but the amplitude of the rhythm varied because of sex and size differences which are discussed later. The metabolic rate of each crawfish was determined before it received the extract of eyestalk. The effect of the extract upon the previously determined metabolic rate was then determined. Experiments and Results Daily rhythm of oxygen consumption of normal Cambarellus. — Normal animals, of which 75 percent were males, were placed in the respirometers and the rate of oxygen consumption over 24 hour intervals was determined. One crawfish was in each respirometer so that the metabolic rate of any one crawfish could be followed, rather than compare the rate of oxygen consumption of different crawfish from different times of day. These observations were made from midnight to midnight on nine days between March 30 and May 12, 1955. The data for the individual crawfish for the nine days were averaged (fig. 1). Data obtained on three other days within this period were similar to the data for the nine days but did 106 Tulane Studies in Zoology Vol. 3 not include a midnight to midnight 24 hour interval and, therefore, could not be averaged with the data of the nine days. As is evident from Figure 1, the metabolic rate of the individual crawfish was continuously changing throughout the 24 hour period. The respir- atory rate was maximal about 6 a.m. with a secondary peak in the 12 M 3A.M. 6A.M. 9A.M. 12 N 3PM. 6P.M. 9P.M. Figure 1. The daily rhythm in rate of oxygen consumption of normal C. shufeldtii. afternoon (3-6 p.m.). Minima occurred between 9 a.m. and noon and 9 p.m. and midnight. No sexual difference in the character of the daily rhythm was observed. The maximal rate of oxygen consumption was three times the mini- mal rate. Normal variations of this sort can explain the diverse rates of oxygen consumption in the literature for any one species. This rhythmic variation of the metabolic rate of individual crawfish is in all probability due to an endogenous activity rhythm. Mildred E. Lowe, a graduate student, observed that this species is most active in the laboratory about 7 a.m. Daily rhythm of oxygen consumption of eyestalkless Cambarellus. — Both eyestalks were removed by transection at their bases and the wounds cauterized to minimize bleeding. Females whose eyestalks had been removed at least 24 hours previously were placed in the respirometers and the rate of oxygen consumption of these eyestalk- No. 6 Fingerman: Oxygen Consumption of Cambarellus 107 less crawfish was determined. Data were obtained from midnight to midnight on three days between April 14 and May 9, 1955 and aver- aged (fig. 2). Results obtained on three additional days were rhyth- mically similar but did not include a midnight to midnight period. A daily rhythm of oxygen consumption in eyestalkless Cambarellus is evident from this figure. The daily pattern of the eyestalkless crawfish differs only slightly in form from the pattern of normal animals. The maximal and minimal metabolic rates occurred at ap- proximately the same times in both normal and eyestalkless crawfish. 3A.M. 6A.M. 9A.M. 12 N 3PM. 6P.M. 9P.M. Figure 2. The daily rhythm in rate of oxygen consumption of eye- stalkless C. shufeldtii. Brown, Bennett, and Webb (1954) found the same is true for the daily metabolic rhythms of normal and eyestalkless Uca pugilator. The amplitude of the curve for eyestalkless animals is 16 percent greater than for normal crawfish. Influence of sex and weight upon the rate of oxygen consumption in normal Cambarellus. — The rate of oxygen consumption of normal male and female Cambarellus was determined for one hour intervals by means of the Warburg respirometer. The data are presented in Table 1. Cambarellus possibly has a metabolic rhythm with a tidal frequency as found in Uca (Brown, Bennett, and Webb, 1954). If true, then one could not be certain that the crawfish would be rhyth- 108 Tulane Studies in Zoology Vol. 3 mically similar at the same hour each day. The decision was made therefore to randomize the data with respect to time of day. Data for both sexes were collected at several times of day and night to randomize the effects of the daily rhythm. The metabolic rates of males and females could be compared with one another because the metabolic rates of individuals from both sexes were determined at TABLE 1. Oxygen Consumption of Normal C. shufeldtii Males Females Oxygen Oxygen Weight (g) Consumption Weight (g) Consumption (ml/g/h) (ml/g/h) 0.12 0.140 0.10 0.280 0.12 0.197 0.11 0.279 0.13 0.277 0.11 0.293 0.13 0.300 0.11 0.331 0.13 0.323 0.12 0.179 0.13 0.654 0.14 0.161 0.15 0.238 0.14 0.182 0.15 0.264 0.15 0.286 0.15 0.268 0.16 0.210 0.15 0.480 0.26 0.307 0.17 0.205 0.28 0.196 0.17 0.307 0.28 0.261 0.17 0.312 0.29 0.238 0.18 0.339 0.30 0.267 0.19 0.203 0.30 0.280 0.19 0.221 0.31 0.164 0.19 0.313 0.31 0.222 0.20 0.369 0.31 0.229 0.21 0.472 0.33 0.152 0.22 0.245 0.33 0.165 0.22 0.427 0.33 0.170 0.23 0.330 0.33 0.245 0.24 0.278 0.35 0.211 0.24 0.279 0.35 0.214 0.24 0.307 0.35 0.342 0.31 0.171 0.36 0.292 0.38 0.121 0.38 0.203 Average 0.18 0.305 0.26 0.230 all times of day. Twenty-six males had an average wet weight of 0.18 grams and an average metabolic rate of 0.305 ml/g/hr. Twenty-eight females had an average wet weight of 0.26 grams and an average metabolic rate of 0.230 ml/g/hr. The males weighed less and had a higher metabolic rate than the females. The difference in metabolic rate was probably due in part to the inverse relationship between metabolic rate and weight. This relationship also seems to hold if the sexes are considered separately. There was probably also a sexual component to the difference in No. 6 Fingerman: Oxygen Consumption of Cambarellus 109 metabolic rate between the males and females. A comparison of males and females of similar weight suggested that males had the higher metabolic rate. Effect of eyestalk removal upon the rate of oxygen consumption of Cambarellus. — The metabolic rate of male and female specimens of Cambarellus was determined for one hour by means of the Warburg respirometer. The animals were then weighed and their eyestalks TABLE 2. Influence of Eyestalk Removal on Oxygen Consumption Oxygen Consumpt: ion After Eyestalk Removal Weight (g) (ml/g/hr) ODays IDay 2 Days 3 Days 4 Days Males 0.18 0.339 0.367 0.19 0.221 0.289 0.21 0.472 0.299 0.22 0.427 0.518 0.23 0.330 0.369 0.13 0.323 0.446 0.867 0.19 0.313 0.242 0.248 0.31 0.171 0.236 0.220 0.13 0.277 0.408 0.215 0.277 0.13 0.300 0.553 0.492 0.423 0.15 0.264 0.438 0.402 0.264 0.24 0.278 0.395 0.373 0.410 Females 0.30 0.276 0.311 0.33 0.165 0.246 0.33 0.170 0.224 0.33 0.245 0.251 0.35 0.214 0.286 0.36 0.292 0.288 0.38 0.203 0.224 0.10 0.280 0.254 0.230 0.28 0.261 0.225 0.268 0.29 0.238 0.286 0.249 0.35 0.211 0.091 0.191 0.28 0.196 0.197 0.243 0.247 0.31 0.164 0.187 0.155 0.139 0.31 0.229 0.239 0.206 0.231 0.33 0.152 0.182 0.206 0.215 0.38 0.121 0.131 0.198 0.198 0.195 removed. The metabolic rate of these animals was subsequently de- termined at 24 hour intervals until death occurred. The observed data are presented in Table 2. To prepare Table 3, the data of Table 2 were averaged according to the number of days the animals of each sex survived. The values were then converted to the percentage of the metabolic rate determined prior to eyestalk removal. For example, the inital value for the animals in the "Destalked 72 hours" category 110 Tulane Studies in Zoology Vol. 3 co W m Q M a O w s K W H I s W ri °5 3 ho ^8 «H OS m m u 0J A 3 oo as Tjl > 03 W m eg 03 01 > 2 o 03 03 Ph CO ow ©to ^jOh oh 03 M »— H c3 -t-> 03 03 Q oo ■<* o H O H O CO H n< t-oo X O H O H c- 0) jM "eS 4J 03 03 P O O c 'So O -U P e> o --* 03 Ph 3 03 o \ \ r— i s II 1) _bp «H ?H 03 Ph Ph 3 No. 6 Fingerman: Oxygen Consumption of Cambarellus 111 was based upon the initial metabolic rate of animals which survived the operation at least 72 hours. As is evident from these averages, the metabolic rate increased following eyestalk removal. In every case where a comparison could be made, the males showed the greater percentage increase. This fact supports the contention of a basic sexual difference in metabolic rate. The percentage increase of the rate of oxygen consumption for both sexes was combined in Figure 3. There was a general trend for the animals surviving longer to have the larger increase in metabolic rate. 2 3 DAYS AFTER EYESTALK REMOVAL Figure 3. The effect of eyestalk removal upon the rate of oxygen consumption. The rate of oxygen consumption is expressed as the percentage increase over the rate determined prior to eyestalk re- moval. The results have been plotted according to the number of days the eyestalkless crawfish survived. Effect of eyestalk extract upon the metabolic rate of Cambarel- lus.— Two experiments involving 11 animals were performed. The metabolic rates of six control and five experimental animals whose eyestalks had been removed at least 24 hours previously were deter- mined for one hour by means of the Warburg respirometer. The experimental group received immediately after the initial determina- tion of the metabolic rate an injection of the equivalent of one eye- stalk in 0.025 ml of extract which was prepared in the following fashion. The eyestalks were removed from several Cambarellus, tritu- rated, and resuspended in a sufficient volume of van Harreveld's solu- tion, which is isotonic with crawfish blood, so that each 0.025 ml of 112 Tulane Studies in Zoology Vol. 3 n < W >-H O H $8 Hw ^ H hh a w < fa o w w 5j H w H H tx. O OS w H « O o 03 m / oo o oo in io h s! co oo th m os co ^OOHHHN © d d o o d 00t-05OlON Tfowo-?|im O rH yH CM CNI CM d do odd be CO C- O "tf C- CM OOHHHN £ oooooo rHr* CMOOOOO 03!0 0)(NtDO OOOHHN OOOOOO a Ot-OOt-N CO O O -^ 00 CO OOHHHN OOOOOO r* I— I cS -t-> CO 0> >> H H3 0) o 0) WNO00OH •^ OS co co o "tf O O i-H T-H CM CM o doodo 0? tO 00 rH CO W Tf JtOt'HlOOTf ^oohhhn d cSdd'oS CO C-O O O rH rj< C5 «# t- (M C- OOHHNN <£ <£ <6 <£ d> ro fl OOHHNO) n OOOOOO +-> w £ o cootj< t- t-o Tj '-H •^ oo th irj os ■* c o o H ih h cm -u o OOOOOO 0) o •r-s icoooTfffi«omt-Tf«oi> COfflmNi005iMiCC-OM© ooohhhnnnmmm Tf(MtO(MCM o t- t-H CO t- O ■<* CI CM O O O rH rH CM d do do d MOOOKJlOOlOt-OlON ^OOfMlOcsCOOOrHoOCMWCl OOHHHNNC0M''l,^',* t-00 t- t> t>00 (M m CO O CM "* O O O O rH rH odd d do D3rHOOC50(MtO(NO)10Ht- C0C000O-<#C-C-rH'^00CMlO OOOrHrHi-HrHCMCMCMCOCO dddddddddddd ■^OOOOOO O OOOOOOOOOOOO 5 rH CM CO "* lO CO CO rH CM CO ■>* lO CO C- CO C5 O rH CM C i i i No. 6 Fingerman: Oxygen Consumption of Cambarellus 113 extract contained the equivalent of one eyestalk. The control group immediately received 0.025 ml of van Harreveld's solution. The averaged results of the two experiments were used to prepare Figure 4. The oxygen consumption of each crawfish used in this 30 60 9 0 120 150 MINUTES 80 210 240 Figure 4. The influence of eyestalk extract upon the rate of oxygen consumption of eyestalkless C. shufeldtii. Circles = control animal's which received injections of saline; dots = animals which received an injection of eyestalk extract; arrow indicates when the injections were administered; ordinate shows the milliliters of oxygen consumed per gram of body weight. 114 Tulane Studies in Zoology Vol. 3 series of experiments is presented in Table 4. In this experiment comparison was made of the metabolic rate of the same crawfish before and after injection, rather than a comparison of the metabolic rates of different crawfish. The metabolic rates of the controls and experimentals were identical prior to the injections. Following the injections the controls showed no change in metabolic rate. The line representing the rate of the control animals paralleled the line drawn with the data obtained prior to the injection. The experimental group showed a decrease in metabolic rate as evidenced by the decrease in slope. One hundred fifty minutes fol- lowing the injections the metabolic rate of the experimental group was 23 percent less than the rate of the controls. Lack of effect of stimulation of the eyestalk stubs. — The metabolic rates of six eyestalkless animals were determined for one hour by means of the Warburg respirometer. The eyestalk stubs were then stimulated by means of an electric cautery and the metabolic rates again determined. The results are presented in Table 5. TABLE 5. Influence of Cautery of Eyestalk Stubs Upon Rate of Oxygen Consumption Oxygen Consumption Oxygen Consumption Percent- Before Cautery After Cautery age Animal (ml/g/hr) (ml/g/hr) Change 1 0.246 0.261 + 6 2 0.191 0.137 —28 3 0.248 0.279 + 12 4 0.224 0.276 + 23 5 0.251 0.224 — 12 6 0.239 0.312 + 31 There was no constant effect. Four of the animals showed an in- crease in rate, two a decrease. The average change was a 6.4 percent increase. Scudamore (1947) found a 56.8 percent increase in meta- bolic rate following cauterization of the eyestalk stubs of Orconectes immunis. Experiments designed to test the effects of extracts of the supraesophageal ganglia with the circumesophageal connectives attached were equally inconclusive. Discussion The existence of a daily rhythm of oxygen consumption in eyestalk- less Cambarellus demonstrated that the sinus gland and x-organ of the eyestalk are not the centers of rhythmical activity in this species. The slight difference in the daily patterns of normal and eyestalkless Cambarellus might have been a modification of the basic metabolic rhythm due to the loss of the endocrine sources in the eyestalks. The higher metabolic rate of eyestalkless crawfish is evident from (1) the greater amplitude of the daily rhythm of eyestalkless indi- No. 6 Fingerman: Oxygen Consumption of Cambarellus 115 viduals and (2) the observations of the effect of eyestalk removal upon the metabolic rate of the same individual from day to day. The crawfish used in the determination of the daily rhythm of eyestalkless animals were females which were shown to have a lower metabolic rate than males. Seventy-five percent of the animals used in the studies of the daily rhythm of normal crawfish were males. The ob- served increase in amplitude of the daily rhythm of eyestalkless craw- fish would probably have been greater than the observed 16 percent if animals of the same sex had been compared. The observed effect of eyestalk extract upon the metabolic rate confirmed the earlier observations of Scudamore (1947) who used a different genus of crawfish. Summary 1. The rate of oxygen consumption of the dwarf crawfish, Cam- barellus shufeldtii, has been continuously recorded for 24 hour periods. 2. Analysis of the data revealed a daily rhythm of rate of oxygen consumption. The rate was maximal around 6 a.m. with a secondary maximum at 3-6 p.m. Minima occurred from 9 a.m. to noon and from 9 p.m. to midnight. 3. Eyestalkless Cambarellus sbufeldtii also had a persistent daily rhythm of metabolic rate. The daily rhythm of eyestalkless individuals differed slightly in pattern from that of normal crawfish. 4. Males weighed less and appeared to have a higher metabolic rate than females. The higher rate was probably due to both the sexual and weight differences. 5. Removal of the eyestalks resulted in an increase in the meta- bolic rate. 6. Extracts of eyestalks decreased the metabolic rate. 7. The metabolic rate of males increased more than the metabolic rate of females after eyestalk removal. This fact is further evidence in favor of a sexual difference in metabolic rate in Cambarellus. References Cited Bauchau, A. G. 1948. Intensite du metabolisme et gland sinusaire chez Eriocheir sinensis. H. M. Edw. Ann. Soc. Roy. Zool. Belgi- que, 79: 73-86. Bliss, Dorothy E. 1953. Neurosecretion and crab metabolism. Anat. Rec, 117: 599. Brown, Frank A., Jr. 1954. A simple, automatic, continuous-record- ing respirometer. Rev. Sri. Instruments, 25: 415-417. Brown, Frank A., Jr., Miriam F. Bennett, and H. Marguerite Webb 1954. Persistent daily and tidal rhythms of oxygen con- sumption in fiddler crabs. J. Cell, and Comv. Physiol., 44: 477- 506. Edwards, George A. 1946. The influence of temperature upon the oxygen consumption of several arthropods. Ibid., 27: 53-64. 1950. The influence of eyestalk removal on the 116 Tulane Studies in Zoology Vol. 3 metabolism of the fiddler crab. Physiol. Comp. et Oecol., 2: 34-50. Scheer, Bradley T. and Marlin A. R. Scheer 1954. The hormonal control of metabolism in crustaceans. VIII. Oxygen consumption in Leander serratus. Pubbl. Staz. Zool. Napoli, 25: 419-426. Scudamore, Harold H. 1947. The influence of the sinus glands upon molting and associated changes in the crayfish. Physiol. Zool, 20: 187-208. Zeuthen, Erik 1955. Comparative physiology (respiration). Ann. Rev. Physiol, 17: 459-482. r rr ' i c £ w <— '^ i e* £ » * j sis s@@iL@(a^r Volume 3, Number 7 February 3, 1956 IDENTIFICATION AND GEOGRAPHICAL VARIATION OF THE CYPRINODONT FISHES FUNDULUS OLIVACEUS (STORER) AND FUNDULUS NOTATUS (RAFINESQUE) JERRAM L. BROWN, DEPARTMENT OF CONSERVATION, CORNELL UNIVERSITY, ITHACA, NEW YORK FEB ? 3 1956 TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and con- tains an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Clark Hubbs, Assistant Professor of Zoology, University of Texas, Austin, Texas. George A. Moore, Professor of Zoology, Oklahoma Agricultural and Mechanical College, Stillwater, Oklahoma. Luis Rene Rivas, Associate Professor of Zoology, University of Miami, Coral Gables, Florida. Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers or volumes may be purchased by individuals, but subscriptions are not accepted. Lists of papers published will be mailed on request. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers or volumes to the editor. Remittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. ZooL Price for this number: $0.50. George Henry Penn, Editor Meade Natural History Library, Tulane University, New Orleans, U. S. A. Assistants to the Editor: Miriam Hale Don R. Boyer £UUL .ill FEB 2 3 195e IDENTIFICATION AND GEOGRAPHICAL VARIATION OF THE CYPRINODONT FISHES FUNDULUS OLIVACEUS (STORER) AND FUNDULUS NOT AT US (RAFINESQUE) JERRAM L. BROWN, Department of Conservation, Cornell University, Ithaca, New York In recent years it has been recognized by some ichthyologists that Fundulus olivaceus is worthy of recognition as a species distinct from the closely related Fundulus notatus. Some observations which par- tially clarify the morphological relationships between these two species are reported here. The author is indebted to Dr. Edward C. Raney under whom the work was done as part of a review of the genus Fundulus which was completed and submitted as a Master of Science thesis at Cornell University in 1954. All of the specimens examined are in the Cornell University fish collection. That Fundulus olivaceus should be recognized as a good species has not been agreed upon by most ichthyologists in the past. Garman (1895: 117) placed notatus in the synonymy of olivaceus. Jordan and Evermann (1896: 659) recognized that southern specimens are larger and darker but did not separate olivaceus from notatus. Al- though both species occur commonly in Illinois, Forbes and Richard- son ( 1920: 213) treated notatus with no mention of olivaceus. Hubbs and Ortenburger (1927: 98), who obviously were dealing with speci- mens of both species, summarized their opinions on the matter as fol- lows: "The specks on the body vary from being diffuse or even indistinct to being sharp, round, and black. We are, however, unable to attach any racial importance to this variation, for it shows no clear- cut geographical relation, and is not always consistent at a single locality." Kuhne (1939: 77) stated, "Two subspecies occur in Ten- nessee, the northern (and more upland) F. n. notatus and the southern lowland F. n. olivaceus (Putnam). The latter has a flatter head and the body is marked by strong blackish spots." Moore and Paden (1950: 88) stated that "F. notatus and F. olivaceus occupy the same habitat (overflow pools, oxbow lakes, and to some extent backwaters) without any apparent interbreeding. A special effort was made to collect pairs in order to determine their characters. Both sexes of each pair proved to be either one or the other of the two forms, thus in some measure, confirming their specific identity. ..." Jurgens and Hubbs (1953) also listed olivaceus and notatus as separate species. Knapp (1953: 89) wrote of F. olivaceus in Texas, "Where its range overlaps with F. notatus the two are usually ecologically separated, F. olivaceus being typically a quiet water form. Near the coastal plain this species inhabits swifter waters." He also stated, "In Texas F. notatus is to be expected in headwaters and fast streams." Bailey, Winn, and Smith (1954: 133) pointed out the striking resemblance of the two species and stated, "it is possible that a more thorough '"0 120 Tulane Studies in Zoology Vol. 3 60 s HO o CO S o < 03 to < % w < CO O Q o w co CM S to to e 5> s s s s co >> o3 Cm 73 CO H o Q «H O J-l (1) 2 55 oo I I I 00© rH CM o in OffiOOjOOOO OOffiOlOOQ CO CMCM c ° v *§« gtf re O "<#CO CO CO CO rH r> to to M CO s « o Eh Q a> 03 cj 03 CO CO CM o 03 S so e so I 2 03 1-1 Ph to >H o " rH «M O Fh IV ,Q 00 oo I I I I CT3 NHIOHCO 0 0)0)0)03 CO 00 Nffi'"* CO o '43 03 I— t o Ch I I I I I I I (DM |HH •^lOOJOOCO N o o rH Tf t- CO M CO © © LO 00 00 rH 03 r— < . d < CD'S O 03 CD a> g ?H _ X o rH 00 » 03 M s o co 0) O 03 No. 7 Brown: Geographic Variation in Fundulus 121 study may prove them to be the genetic variants of a single species." They recognized that evidence from Moore and Paden (1950: 88) suggests that these are two full species sympatric in some parts of their ranges. The evidence from my studies supports the recognition of olivaceus as a valid species. Methods Dorsal and anal rays were counted at their bases, the last two rays never being counted as one, as is the custom in counting for certain groups. Standard length, caudal peduncle depth, depressed dorsal and anal fins, bases of dorsal and anal fins, and lateral-line scales were measured or counted according to the methods of Hubbs and Lagler (1947: 8-15), except that the most anterior scale counted was the one in which the center of the exposed field of the scale lay exactly on, or just posterior to, a vertical line through the upper extremity of the gill slit. Scales around the caudal peduncle (usually, but not necessarily, the least count) were counted vertically at a point half way between the posterior bases of the dorsal and anal fins and the upper and lower procurrent caudal rays. For methods of calculation and interpretation of the coefficient of divergence see Mayr, Linsley and Usinger (1953: 146). Explanation of Figures In the figures the range is shown as a single, heavy, horizontal line; the mean by a short, pointed, vertical line; one standard deviation on either side of the mean by a hollow bar; and two standard errors on either side of the mean by a solid black bar. Regardless of sample size the denominator used in calculating the standard deviation was always "N — 1". In general, for normal distributions, when the black bars for two samples do not overlap it is safe to conclude that the difference between the two means is probably not due to chance. When the hollow bars do not overlap, approximately 84% or more of the specimens are separable. Hubbs and Hubbs (1953) gave de- tails for interpreting this type of diagram. Because the distributions only approach normal, statistical interpretations should be made on the conservative side. Variation in Fundulus olivaceus In olivaceus the dorsal and anal rays (Tables 1, 2; figs. 1, 2) are fewer in specimens from eastern Gulf Coast drainages than in those from the Mississippi Valley. With respect to these characters the specimens from eastern Louisiana clearly fit with those from the Mississippi Valley. There is probably a clinal intergradation between the Alabama-Florida and Louisiana populations since the sample from the Biloxi River of Mississippi is intermediate; additional material may show that this trend is continued in Texas populations. A line drawn between 9 and 10 dorsal rays separates 83% of 104 Mississippi Valley specimens from 81% of 70 Alabama-Florida speci- mens; average separation 82%; coefficient of divergence 0.80. A 122 Tulane Studies in Zoology Vol. 3 s s 'a 5S < ■» o e & PQ 6h CO >< ««! ►J o « w a CO 60 £ to s 3 s s I*. eo tH w 13 o 3 co C o o a* | lO OlO CM tH OiffiNH | CO tH (MCO t- co OH CO OlOOM^ CM * U0 OS CO CM CM CMU3 I I ©CO in t- h io m io co i-l i-l CM OS t- t>oooo I iH OS lO to co m c . c c . • 1) C O ,JJ dS^gcS ^ S« «« re CM tH tH tH tH tH -tf CM00O OCM O HCOCMH "* CM CM OS t- t- CM 00 CO tH tH CO i-l 00 tr- i CM 13 > co 1/1 CO CO Q o>Ph «-§ <2 ^g ° 2^ ^ o ci cj PS Bl Op fi O cS « .2 « LO IC co CM «o S e o CO s s ■>* CO CO >> CS M 13 c O cS Eh O No. 7 Brown: Geographic Variation in Fundulus 123 8 DORSAL RAYS 9 10 II 12 N 31 25 29 12 38 20 10 04 70 62 85 18 Figure 1. Dorsal ray counts. Fundulus olivaceus: A. Southern Illi- nois; B. Arkansas River, Ark.; C. Eastern Louisiana; D. iBiloxi River, Miss.; E. Alabama River; F. Pensacola Bay drainage; G. Choctawhatchee River; H. Total Mississippi Valley and Louisiana; I. Total Alabama River to Chattahoochee River. Fundulus notatus — A. Northern Illinois; B. Total Mississippi Valley and Tombigbee River; C. Galveston Bay drainage, Texas. line drawn between 11 and 12 anal rays separates 89% of 104 Mis- sissippi Valley specimens from 53% of 70 Alabama-Florida speci- mens; average separation 71%; coefficient of divergence 0.54. The number of scales in the lateral line (Table 3, fig. 3) is usually 34 or fewer, but in the three easternmost populations treated, the frequency distribution shows an unusual number with 35 scales. Samples from the Alabama River System are similar to western popu- lations; whereas in numbers of dorsal and anal rays the Alabama population is similar to those from the eastern Gulf. A line drawn between 34 and 35 scales separates 59% of 32 specimens from the drainage systems of Pensacola Bay, Choctawhatchee River and Chat- tahoochee River from 89% of the rest of the specimens examined (140); average separation 74%; coefficient of divergence 0.52. The number of scales around the caudal peduncle (Table 4, fig. 4) Al jz -*- 1 B i- -A- 1 A C 124 Tulane Studies in Zoology Vol. 3 CO s © s eo •I k Q < oo s W s a m k <3 H C/j UJ J «! o m ►J < a H < •J &. o OS u M & 55 3 CM s £ CO CO S fc, co ^ CD y Xfl a c3 CD +-> c« O a> co CO 3 CM co CO c o «j 13 p- o a. to CM CM rfOOOl in aj:~4 rH t-r-l | tH CO CO CO (MOO I ID OOTf 00 5BMO CO rj5 ■>* Lfi CO coooco O OON lO COCO CM 00 00 co CM CO I I $ o P a CO o £ o o3 03 +» CO ej c 2 CM oo CO CO CM eo s so CO S »*o s *©- s s k CO CO CD a3 CD OQ 03 «H CO O CO CD 3 Z CM co CO e o 3 a. o a. t- i i CM 00 I co t-eoocM © CM CM CO CO CO co co eo co co CO"^ CMC5-rj< CM Mil! eo I I co CM tH CM lO Tf I CO rH | o < 3 ".J CD o«hS CO o CI-0 H _ CD C ^5 O CD-g O 00 CM CM co as co m 00 c~ * 1 CD O CM lO I Q >» ai M c o co r-4 CD 03 > O 03 Eh O No. 7 Brown: Geographic Variation in Fundulus 125 is 16 in most Gulf Coast specimens and varies from 16 to 20 in speci- mens from the central Mississippi Valley; there seems to be a cor- relation with latitude for this character. A line drawn between 16 and 17 separates 76% of 72 central Mississippi Valley specimens from 72% of 99 Gulf Coast specimens; average separation 74%; coef- ficient of divergence 0.67. The coefficient of divergence is not applicable in this instance since the standard deviation for the Mis- sissippi Valley sample, 1.30, is more than IVi times the standard deviation of the Gulf Coast sample, 0.76. There is a difference in average body form between specimens of olivaceus from the Mississippi Valley and specimens from the Gulf Coast. The latter have a slimmer caudal peduncle ( Figure 5 ) , and their bodies are generally less deep and less wide. The following generalizations seem appropriate. First, it is seen that the various characters which vary geographically are not well coordinated with each other. For example, the breaks between high and low numbers of lateral-line scales, fin rays, and caudal peduncle scales are located in different geographical areas. The differences in ANAL RAYS 10 II 12 13 14 N A I— ^ 31 B C 25 29 D ii 12 E F G H -^-ii 38 20 10 104 1 A r-rfk-i 70 62 B i i i 85 C A^ 19 Figure 2. Anal ray counts. Fundulus oliv iceus — A. -I. s ame as fig. 1. Fundulus notatus — A.-C. same as fig. 1. 126 Tulane Studies in Zoology Vol. 3 LATERAL LINE SCALES 32 33 34 35 36 A — i ,' X ' — i B 1 1 — ^ — 1 C D E 1 ^ i F 1 * r ihh G H r^i 1 1 — i— N 30 23 21 12 35 20 10 32 40 26 45 8 Figure 3. Lateral line scale counts. Fundulus olivaceus — A. South- ern Illinois; B. Arkansas River, Ark.; C. Eastern Louisiana; D. Biloxi River, Miss.; E. Alabama River; F. Pensacola Bay drainage; G. Choctawhatchee River; H. Total Pensacola Bay to Chattahoochee River; I. Total Mississippi Valley and East along Gulf Coast through the Alabama River. Fundulus notatus — A. Northern Illinois; B. Total Mississippi Valley and Tombigbee River; C. Galveston Bay drainage, Texas. proportions and number of scales around the caudal peduncle are ap- parently correlated with latitude. The number of anal and dorsal rays varies in an east-west direction. The highest lateral line frequency is restricted to a relatively small area in Alabama and Florida. These characters might be employed to divide the species into several races (not subspecies), but the author chooses to present only a general picture of variation for each important character. Range of Fundulus olivaceus The range extends from the Okefinokee Swamp, Georgia (?) ("F. notatus" of Fowler, 1945: 244), the Chattahoochee (CU 16081 and 15997) and Choctawhatchee River systems of Alabama and Florida, and the Clinch River System of Tennessee (CU 19148), to Texas (Jurgens and Hubbs, 1953; Knapp, 1953: 89) and the Ar- No. 7 Brown: Geographic Variation in Fundulus 127 CO s © s CO 8 s 8 8 Q < CO 8 e 5> co s 8 8 a S3 a ta Oh Q < o a z o o OS o w w -j < w El. O 55 3 CO S to cj 5 5? co 8 8 xn ■>> CO r W (V d d 0 Oh c« c3 O SH O u CD ,d o CM O oo co 3 £ lo ■<* d _o cs »— « & o a, cm O t-I t- Tj< -r# 00 CO lo co co^nn^ CM CM TfHotcmoo t- 00 SO CO t- t- C- Oi tH t> -<* rf CM CM -* I CM CM 00 | HHCC tH OS | O i-l "tf cm-* Moo CM ** tH LO (M CO I I I I I I I I I I I d d s Id rH r<3 ,0h . cd rt ^jSrC CD CD • "£ d w-d _^ o g.S eyX-* o co lOlOOOCO oo c- t- to co t- t- 00 -<* CM CO LO t-^ co lo co co co co HN10C350N CN tH CO tH i-H - I I I I I I 00 I I I I I I lo lo I -^ i-i i—i CO lOHt'NHH 00 "* LO 00 • I CM i-H N |H I I I I rH I I I I rc3 > CO 2 CS Q o>Oh /r< ^ a) CO -2'fl C3§ •J r +-> 5 . CO O H-> cs.„-^ cu-dx WOh^CuOO LO CC to CM 80 CO 3 ■^ (M 8 « w W CD Ci -3 ^ d d co f-J 00 S c3 o ?t- cy ^ s d CO co d _o cS d o Oh co I I I CMLOOCM t> t-^OOOO CO-^ CMOJ CM OH O) CM C-tH coco l-H T}< CI CO I I CO I I o Fh 128 Tulane Studies in Zoology Vol. 3 SCALES AROUND CAUDAL PEDUNCLE 14 15 16 17 18 19 20 N 29 24 21 12 35 19 10 72 99 26 41 23 Figure 4. Scales around caudal peduncle. Fundulus olivaceus — A. Southern Illinois; B. Arkansas River, Ark.; C. Eastern Louisi- ana; D. Biloxi River, Miss.; E. Alabama River; F. Pensacola Bay drainage; G. Choctawhatchee River; H. Total Mississippi Valley; I. Total Gulf Coast. Fundulus notatus — A. Northern Illinois; B. Total northern specimens; C. Total Galveston Bay and Tombigbee River drainages. kansas and Red River Systems of eastern Oklahoma (George A. Moore, personal communication), and north to Morgan County, Mis- souri (CU 11227), Union County, Illinois (CU 3464 and 3476), and western Kentucky and Tennessee (other CU collections). Material Examined Missouri R., Mo. — Morgan Co.: Little Gravois Cr., 2Vi mi. N.E. of Gravois Mill, CU 11227, 7 specimens (standard length 38-62 mm). Southern Illinois— -Union Co.: E. of Cobden, CU 3464, 19 (22-61); E. of Anna, CU 3476, 12 (37-45). Clinch R., Tenn.— Anderson Co.: Poplar Cr., 5.8 mi. N.E. of Oliver Sprs., CU 19148, 1 (41). Western Tennessee. — Houston Co.: White Oak Cr., 8 mi. from McKinnon, Old Bridge at Crosswell's Farm, CU 23114, 7 (38-55). White R., Mo.— Butler Co.: Little Black R., 2.4 mi. E. of Fairdealing, Rt. 14, CU 24278, 4 (25-51). Arkansas R., Ark.— Pope Co.: Illinois Bayou, 4.2 mi. W. of Russelville, Rt. 22, CU 24368, 12 (25-37). Franklin Co.: White Oak Cr., 7.4 mi. E. of Ozark, Rt. 64, CU uncataloged, No. 7 Brown: Geographic Variation in Fundulus 129 13 (25-60). Eastern Louisiana. — West Feliciana Par.: Alexander Cr., trib. Thompson Cr., 1.1 mi. E. of jet. Rt. 65 and 61 with Rt. 35, CU 16302, 12 (21-53). Livingstone Par.: trib. Colyell Cr., 5.7 mi. W. of Livingstone, Rt. 190, Amite R. drainage, CU 15529, 5 (26-72). Tangipahoa Par.: trib. Selser Cr., 3.3 mi. E. of Hammond, Rt. 190, Pontchartrain drainage, CU 13945, 6 (26-50); Natalbany R., 0.8 mi. W. of Baptist, Rt. 190, Lk. Maurepas drainage, CU 21552, 6 (36-56). Biloxi R., Miss. — Stone Co.: headwaters Biloxi R., 12.2 mi. S.W. of Wiggins, CU 16636, 12 (26-58). Alabama R., Ala.-Uz.con Co.: trib. Sawacklahatchee Cr., 1.7 mi. W. of Society Hill, Rt. 80, CU 16028, 18 (26-58); trib. Cobebee R., 3-9 mi. S. of Tuskegee, Rt. 29, CU 14049, 16 (25-55); Sawacklahatchee Cr., trib. Uphapa Cr., 5.9 mi. W. of Society Hill, CU 16003, 4 (38-58). Pensacola Bay Drain- age.— Okaloosa Co., Fla.: Blackwater R. 4.3 mi. N.W. of Baker, CU 12665, 1 (48); trib. Blackwater R., 100 yds. E. of Santa Rosa Co. line, Rt. 4, CU 16705, 7 (31-47); Yellow R., trib. Shoal R., 3.2 mi. E. of Crestville, CU 12156, 2 (47-52). Santa Rosa Co., Fla.: Sweetwater Cr., 12.4 mi. N.W. of Baker, Rt. 4, Blackwater R. drainage, CU 12141, 3 (42-47). Walton Co., Fla.: Gum Cr, trib. Shoal R, 5.9 mi. N.W. of DeFuniak, CU 12125, 3 (22-48). Escambia Co, Ala.: Franklin Mill Cr, 3.9 mi. S.W. of Brewton, Rt. 29, Conecuh System, CU 14011, 2 (33-46). Conecuh Co, Ala.: Jay Br. of Mill Cr, 7.4 mi. E. of Evergreen, CU 16143, 1 (73); Boggy Br, trib. Sepulga R, 4.8 mi. S.W. of McKenzie, Rt. 84, CU 16204, 1. Choctawhatcbee R., Ala.— Henry Co.: 5 mi. W. of Graball, Rt. 10, CU 17143, 10 (30-50). Chattahoochee R., Ala. — Barbour Co.: Barbour Cr, 2.3 mi. S. of Eufaula, CU 16081, 1 (50). Lee Co.: Uchee Cr, 0.7 mi. E. of M, CU 15997, 1 (56). Variation in Fundulus notatus A collection of 19 specimens of F. notatus from the Galveston Bay drainage of eastern Texas differs considerably from typical Illinois and Missouri samples in color, proportions, and numbers of scales and fin rays. In general it may be said that these Texas specimens dif- fer from Illinois populations of notatus in many of the same ways that olivaceus differs from notatus. In the Texas specimens the lateral band is blacker, more intense, and has a more even edge; the cross bars are notably weak in males; and the predorsal stripe is less conspicuous. The spotting on the vertical fins is finer and less regular. In proportions the body is much less robust, less wide, less deep, and generally more attenuate. The head is definitely narrower. Fig- ure 5 shows the difference in relative depth of the caudal peduncle between male specimens of notatus from Texas and from Illinois and Missouri. In Texas specimens the muzzle appears more pointed from the side, and the premaxillary appears smaller when viewed from above. Texas specimens have more anal rays (Table 2, fig. 2). A line drawn between 12 and 13 separates 84% of the 19 Texas specimens 130 Tulane Studies in Zoology Vol. 3 from 88% of 85 more northern and eastern specimens; average sepa- ration 86%; the coefficient of divergence is 0.94, but the standard deviation of the Texas sample is more than twice that of the northern and eastern sample. Texas specimens also average higher in number of dorsal rays; a line drawn between 9 and 10 separates 89% of 18 specimens from 75% of 85 northern and eastern specimens; average separation 82%; coefficient of divergence 0.74, but unreliable because of the difference in standard deviations. In Texas specimens the number of scales in the lateral line (Table 3, fig. 3) averages higher; 61% of 18 specimens being separable from 87% of 45 other speci- mens by a line between 33 and 34; average separation 74%; coef- ficient of divergence 0.69. In northern collections of notatus the number of scales around the caudal peduncle (Table 4, fig. 4) is usually higher than 16; however, 3 of the 4 specimens from the Tombigbee system of Alabama and 16 of the 19 Texas specimens have 16 scales. A line drawn between 16 and 17 separates 83% of CAUDAL PEDUNCLE DEPTH INTO S. L. 7 8 9 10 x i ■" ~r 40 e 50 60 rP D ■ • o % *• I • •• n NORTHERN NOTATUS O TEXAS NOTATUS | NORTHERN OLIVACEUS A GULF COAST OLIVACEUS Figure 5. Caudal peduncle depth in relation to standard length in males of northern and southern populations of Fundulus notatus and Fundulus olivaceus. the 23 southern specimens from 85% of 41 more northern specimens; average separation 84%; coefficient of divergence 0.81. It is apparent that the pattern of geographical variation in F. notatus is strikingly similar to that found in olivaceus. Both are slimmer, less robust, and have somewhat fewer scales around the No. 7 Brown: Geographic Variation in Fundulus 131 in W PQ S o a fa o w o 21 •J H O < Q fa >— i fa Q O a 2 oo S 00 i-H Q < W K O o to s » H 3 I fa o fc o t— ( fa a © R C8 R 03 R o3g<" 43 o ° bo3 h a -a c oT 03 c 03 Cj 03 £ 3 ^ ^3 03 o R 03 T3 3 V 5 bo R 03 R 03 P 5 3 R 543 c R 0) 3 3 o R 02 bl R OS ~ DO 3 0) g r; to m R O 02 73 O 03 -^42 bOp* 3 03 43*? §1 0) - 3 13 T3 03 3 .5 w g«H ft O 03 c r.r o be S'§ R~-U 03 CO bo 3 3ft ►J 03 3 01 ^ M u ? O) J- s o R CD u C3 43 ^ 03 TS 1) c 3 O O 91 — , T3 00 AS „ u 1/3 cfl 3X o ri *H u 01 P. 43 o O T3 3 3 03 fg •a ? S3 2 •~ S .3 S3 boS 03 o .Ss 03 C g.2 S3 -42 03 '^ 33 CO 3;3 3 03 > 03 03 R O S4 03 05 =+-1 i— I 42 O S3^T t>, 3 4VT3 3 a v OJ m W R 03 c o R ft 03 CO 03 •J O CO R 03 a 03 03 ^J° 03." 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I 03 f** 03 — O] R 03 — » 03 4^ 3 «3 0) ~ ^ t3;±3 ^(3 3 R "S'O 03 ^ 05 03 03 03 3S T3 05 03 -S 1— • 03 03 Q, S3 -r T3 S3 03 DQ 03 03 ^^ R 03 O 03 *0 R 03 Q Ph R 03 o R 05 S3 OS 03 R 05 43~4*i 03 O ftj« > >> ^3.3. 03 O 03 03 03 03 03 CO CO 05 3 03 0) R O s T3 03 O R 42 05 03 S 03 R O R O CO 03^ ft 03 O 1— 1 ■— ' 42 c ( > >> j-j'S 13 ►? w « c 13 S3 03 «H o 03 03 03 42 +-> 3 O 42 03 C e bo 05 O S C5 03 T3 O O u t-I 03 03 R 73 2 O .3 O 42 T3 3 05 IS 05 03 43 R 03 ft 03 03 T3 03 03 h R bO 03 03 05-3 ft R-C 03 03 fe 03 > ^ Q » -o o 42 -3 3 05 T3 05 03 45 ft 03 0) -3 03 03 iJ 03 T3 03 fe bo^ 05 03 R M 3 03 T3 03 "3 3 3 O R 03 R O T3 3 13 « R"3 S3> 03^ flft _ "to 03 03 03 --H 43 03 05 02 w^ 11 C 3 - 43 03 J- 43 S8 R R 3 03 o 13s >a w 03 1) 13 13 > 3 • PH 3 ft ft 43 OJ -M 09 ft ro 03 03 ~z g 03 O •S S >» ^ft-° R p-i — "^ ? rj » Pi »3 J» R 3 3 O oS 03 Q U O -3 03 O ft R 03 3 *> w P R 03 O ^1 3 oS 'rt ^ >i ^ R 3 « § Pi 132 Tulane Studies in Zoology Vol. 3 caudal peduncle in the south; and both species have a lower number of dorsal and anal rays in eastern populations. Range of Fundulus notatus The range extends from Mitchell and Grundy counties of north- eastern Iowa (Harlan and Speaker, 1951: 137), southeastern Wis- consin (both sides of the divide), southern Michigan, and the prairie regions of western and central Ohio (Hubbs and Lagler, 1947: 78) south to Kentucky, the Duck River of Tennessee (Miller, 1955: 10), the Gulf drainages from the Tombigbee River System of Alabama (CU 15511) to the Guadalupe River drainage of Texas (Hubbs, Kuehne, and Ball, 1953: 231), and west to Kay, Creek, and Johnston counties of eastern Oklahoma (Moore, personal communication) , and Kansas (Miller, ibid.). Material Examined Northern Illinois. — Cook Co.: Des Plaines R., at bridge, Deerfield Rd., CU 17975, 8 specimens (standard length 32-50 mm). Lake Co.: Des Plaines R, bridge, Rt. 5 9 A, CU 18006, 11 (35-51); Des Plaines R., bridge, Rt. 22, CU 17941, 3 (42-46). Kanakee Co.: trib. Iroquois R., 4 mi. S. of Kanakee, CU uncataloged, 36 (small ad.). Livingston Co.: Vermillion R, CU 3399, 4 (37-46). Marion Co., Ill.—N. of Centralia, CU 3432, 8 (35-51). Meramec R., Mo.— Dent Co.: 2 mi. N.W. of Short Bend, CU 10781, 2 (32-42). Western Tennessee.— Cheatam Co.: White's Cr., 1 mi. N. of Bordeaux, Rt. 41 A, CU 22146, 9- Tombigbee R., Ala. — Green Co.: trib. Tombigbee R., 0.8 mi. N.E. of Boligee, Rt. 11, CU 15511, 4 (30-37). Galveston Bay Drainage, Texas.— Montgomery Co.: 2 mi. W. of Conroe, Rt. 105, CU 21930, 18 (23-49). Walker Co.: Country Campus, Sam Houston S. I. C, 11 mi. E.N.E. of Huntsville, CU 15286, 1 (35). Discussion The characters which have been found most useful in separating these two closely related species are summarized in Table 5, which is taken for the most part from the one prepared by Carl L. Hubbs in Moore and Paden (1950: 88). Although the main differentiating characters are those of coloration, there also are differences in scala- tion, fin rays, proportions, and degree of sexual dimorphism. Fundulus olivaceus is the slimmer, more attenuate species in a given region although this character varies from north to south. Figure 5 illustrates that, for a given size, when northern or southern popula- tions are compared, olivaceus is found to have a slimmer caudal ped- uncle on the average than notatus. It also demonstrates that southern populations of each species have slimmer caudal peduncles than their conspecific northern populations. It may be seen from Figure 6 that in northern populations notatus exhibits a definite difference between the sexes in depth of caudal peduncle, the females being slimmer at the same standard lengths. However, in northern populations of olivaceus there is no obvious No. 7 Brown: Geographic Variation in Fundulus 133 CAUDAL PEDUNCLE DEPTH INTO S. L 7 8 9 10 x UJ a a) NOTATUS MALES NOTATUS FEMALES — — -OLIVACEUS MALES OLIVACEUS FEMALES Figure 6. Sexual dimorphism of caudal peduncle depth in relation to standard length in Illinois and Missouri populations of Fundulus notatus and Fundulus olivaceus. Number of specimens: F. notatus ($=17, $=10), F. olivaceus ($=11, 9=21). The polygons encompass the total range of variation encountered in each case. sexual dimorphism in this character. In respect to length of dorsal and anal fins, measured either at their bases or from origin to tip of longest depressed rays, the same relationship exists. The males of notatus have longer fins and the females shorter ones than equal-sized specimens of both sexes of olivaceus. Summary The evidence that olivaceus and notatus are separate species may be summarized as follows: (1) Specimens of the two forms differ not only in several aspects of coloration, but also in proportions, degree of sexual dimorphism, and to a certain extent in scalation and number of fin rays. ( 2 ) Although notatus extends farther north and olivaceus reaches its greatest abundance in the south, their ranges overlap broadly. (3) The only cases of cohabitation which have been in- vestigated have yielded no positive indication of interbreeding (Moore and Paden, 1950: 88). Both species are slenderer and have fewer scales around the caudal peduncle in the south, and both have fewer dorsal and anal rays in the east. References Cited Bailey, Reeve M., Howard E. Winn and C. Lavett Smith 1954. Fishes from the Escambia River, Alabama and Florida, with 134 Tulane Studies in Zoology Vol. 3 ecologic and taxonomic notes. Proc. Acad. Nat. Sci., Phila., 101: 109-164. Forbes, Stephen Alfred and Robert Earl Richardson 1920. The fishes of Illinois. Nat. Hist. Surv. III., 2nd ed., 3: i-cxxi, 1-357, many figs. Fowler, Henry W. 1945. A study of the fishes of the southern Pied- mont and Coastal Plain. Monogr. Acad. Nat. Sci. Phila., 7: i-vi, 1-408, figs. 1-313. Garman, S. 1895. The cyprinodonts. Mem. Mus. Comp. Zoul, 19: 1-179, pis. 1-12. Harlan, James R. and Everett B. Speaker 1951. Iowa Fish and Fishing. Iowa State Cons. Comm., pp. 1-238, pis. 1-22. Hubbs, Carl L. and Clark Hubbs 1953. An improved graphical analysis and comparison of series of samples. Systematic Zool., 2: 49-56, 92, figs. 1-4. Hubbs, Carl L. and Karl F. Lagler 1947 (and second printing 1949). Fishes of the Great Lakes region. Bull. Cranbrook Inst. Sci., 26 : i-xi, 1-186, pis. 1-26, figs. 1-251. Hubbs, Carl L. and A. I. Ortenburger 1929. Fishes collected in Oklahoma and Arkansas in 1927. Publ. Univ. Okla. Biol. Surv., 1: 45-112, pis. 1-13. Hubbs, Clark, Robert A. Kuehne and Jack C. Ball 1953. Fishes of the upper Guadalupe River, Texas. Texas Jour. Sci., 5: 216- 244. Jordan, David Starr and Barton Warren Evermann 1896. Fishes of North and Middle America. . . . Bull. U. S. Nat. Mus., 47, Pt. 1: i-lx, 1-1240. Jurgens, Kenneth C. and Clark Hubbs 1953. A checklist of Texas fresh-water fishes. Texas Game and Fish, 11: 12-15. Kuhne, Eugene R. 1939. A Guide to the Fishes of Tennessee and the Mid-South. Tenn. Dept. Cons., Nashville, Tenn., pp. 1-124, figs. 1-81. Mayr, Ernst, Gorton E. Linsley and Robert L. Usinger 1953. Methods and Principles of Systematic Zoology. McGraw-Hill Book Co., New York, pp. i-ix, 1-328, figs. 1-45. Miller, Robert Rush 1955. An annotated list of the American cyprinodontid fishes of the genus Fundulus, with the descrip- tion of Fundulus persimilis from Yucatan. Occ. Pap. Mus. Zool. Univ. Mich., No. 568: 1-25, figs. 1-2. Moore, George A. and John M. Paden 1950. The fishes of the Illinois River in Oklahoma and Arkansas. Amer. Midi. Nat., 44: 76-95. r f ' <■ / <_ovy V^/J /ti a /7 5*_J i^il&^h sip 13 is) as 3M ^(D(DIL®OT Volume 3, Number 8 April 12, 1956 THE PHYSIOLOGY OF THE MELANOPHORES OF THE ISOPOD IDOTHEA EXOTICA MILTON FINGERMAN, DEPARTMENT OF ZOOLOGY, NEWCOMB COLLEGE, TULANE UNIVERSITY, NEW ORLEANS, LOUISIANA KUS. COK?. ZCQL APR I 7 tm IMQWn (..; .«l>l.J MHER3ITY TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and con- tains an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Frank A. Brown, Jr., Professor of Zoology, Northwestern Uni- versity, Evanston, Illinois L. H. Kleinholz, Professor of Biology, Reed College, Portland, Oregon Paul A. Wright, Assistant Professor of Zoology, University of Michigan, Ann Arbor, Michigan Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers or volumes may be purchased by individuals, but subscriptions are not accepted. Lists of papers published will be mailed on request. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers or volumes to the editor. Remittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zool, Price for this number: $0.30. George Henry Penn, Editor Meade Natural History Library, Tulane University, New Orleans, U. S. A. Assistant to the Editor: Don R. Boyer VA~ //Cew tfrfa*,) ERRATUM Tulane Studies in Zoology, volume 3, number 8 Through a regrettable error the isopod used by Dr. Milton Fingerman in his study of melanophore physiology was mis-labeled Idothea exotica. The correct name for this isopod is Ligia exotica. MUS. COMP. ZfiOL UIIUY JUL Q iqs^ HARVARD * - STY LIBRARY 2 7 195E HARVARD - !TY THE PHYSIOLOGY OF THE MELANOPHORES OF THE ISOPOD IDOTHEA EXOTICA 1 MILTON FINGERMAN, Department of Zoology, Newcomb College, Tulane University, New Orleans, Louisiana Alteration of body color in isopods was first described by Matz- dorff ( 1883). He noted that specimens of Idothea tricuspidata would blanch upon a white background because of pigment concentration and darken on a black background because of pigment dispersion in the melanophores. Melanin of isopods whose eyes had been either destroyed or covered with an opaque material dispersed to the same extent as the melanin of normal isopods on a black background as demonstrated in Ligia oceanica by Tait (1910), in Idothea tricuspidata by Pieron (1914), in Ligia baudiniana by Kleinholz (1937), and in Ligia exotica by Enami ( 1941 ) . Daily rhythms of color change have been described in a few species of isopods, e.g. in Idothea tricuspidata by Menke (1911) and Pieron (1914) and in Ligia baudiniana by Kleinholz (1937). Specimens of Idothea tricuspidata and Ligia baudiniana maintained in constant darkness darkened by day and lightened by night because of rhythmi- cal migration of melanin within the chromatophores. The pigmentary rhythm was not present in Ligia baudiniana kept on a black back- ground under constant illumination; the pigment remained maxi- mally dispersed throughout the 24-hour day (Kleinholz, 1937). Color changes in isopods, just as in other crustaceans, are controlled by hormones rather than nerve impulses (Brown, 1952). Isopods form a diverse group with respect to the endocrine control of their chromatophore systems. Head extracts of some species of isopods caused pigment concentration alone when injected into isopods (Kleinholz, 1937; Okay, 1945a, b; Suneson, 1947; Carstam and Sune- son, 1949); head extracts of another species dispersed pigment only (Enami, 1941); and extracts of tissues of still another species caused both pigment concentration and pigment dispersion (McWhinnie and Sweeney, 1955). In species which produce one hormone only, e.g. a pigment-dispersing principle, melanin concentration is assumed to be due to removal of darkening hormone from the blood. Kleinholz (1937) demonstrated that head extracts of Ligia baudini- ana caused pigment concentration when injected into specimens with dispersed melanin. Head extracts had no dispersing effect upon con- centrated pigment. Smith (1938) postulated a dual endocrine control of the chromato- phores of Ligia oceanica. On the basis of experiments in which dif- ferent portions of the compound eye were either covered with an opaque material or differentially stimulated by light and background, 1 This investigation was supported by grant No. B-838 from the National Institutes of Health. 140 Tulane Studies in Zoology Vol. 3 he concluded that stimulation of the dorsal ommatidia results in re- lease of darkening hormone and stimulation of the lateroventral om- matidia results in release of lightening hormone. Enami (1941) found that blood transfused from a dark to a light specimen of Ligia exotica caused melanin dispersion. Extracts of heads of Ligia exotica also caused pigment dispersion. In a few experiments Enami observed that a transitory pigment concentration was caused by the head extracts and transfused blood before the melanin dispersed. Nagano (1949) reported quite different results from those reported by Enami (1941) for head extracts of Ligia exotica. Nagano reported concentration of melanin following injec- tion of Ligia exotica head extracts into Ligia exotica. Another investigator, Okay, noted that extracts of heads of Sphae- roma s erratum ( 1945a) and Idothea baltica, Armadillidium granu- latum, and Ligia italica (1945b) produced only melanin concentra- tion when injected into specimens of the same species. Suneson (1947) and Carstam and Suneson (1949) demonstrated that heads of Idothea neglecta also cause melanin concentration when injected into isopods whose pigment was maximally dispersed. In a few ex- periments Carstam and Suneson (1949) observed some pigment dis- persion 60 to 120 minutes after injection of the head extracts into isopods whose pigment was concentrated. These investigators also observed that extracts of heads of Idothea neglecta both dispersed and concentrated the red pigment of the prawn Leander adspersus. Structures have been described in the isopods Oniscus asellus by Walker (1935) and in Trachelipus rathkei by McWhinnie and Sweeney (1955) which are similar in appearance to the sinus glands of the more highly evolved crustaceans. Histological changes during the intermolt cycle which are suggestive of a functional intervention by the sinus glands in the molt cycle have been described in Oniscus asellus by Gabe (1952a) and in Sphaeroma serratum by Gabe (1952b). McWhinnie and Sweeney (1955) have demonstrated conclusively that two chromatophorotropins are produced by the terrestrial isopod Trachelipus rathkei. These investigators demonstrated that extracts of sinus glands, optic tracts, and cerebral ganglia from Trachelipus rathkei dispersed the red pigment of a crawfish Cambarus sp. Cir- cumesophageal connectives and thoracic nerve cord extracts concen- trated the same pigment. The responses of Trachelipus itself to the extracts could not be interpreted readily although there was indication from the data that the chromatophores of Trachelipus responded in a manner opposite to the chromatophores of Catnbarus. Preliminary experiments have indicated that the endocrine control of the chromatophores of the coastal isopod Idothea exotica is differ- ent from that reported in the literature for other species of Idothea. The present study was undertaken, therefore, to investigate in detail the physiology of the chromatophore system of Idothea exotica. No. 8 Fingerman: Melanophores of ldothea 141 Materials and Methods Specimens of ldothea exotica were collected during July and August, 1955, on pilings along the shore of Lake Pontchartrain at Point Aux Herbes, 15 miles northeast of New Orleans, Louisiana. The stock supply of isopods was kept at 22-24 °C in loosely covered glass jars. Water was placed in the containers in order to maintain a high humidity. The method devised by Hogben and Slome (1931) was employed in order to stage the chromatophores. According to their scheme stage 1 represents maximum pigment concentration, stage 5 maximum pigment dispersion, and stages 2, 3, and 4 the intermediate conditions. Chromatophores on the dorsal surface of the isopods were staged with the aid of a stereoscopic dissecting microscope and reflected light. Experiments and Results Background responses of ldothea exotica. — Specimens were collected in the morning and returned to the laboratory by noon. At 1:30 P.M. two lots of 10 individuals each were selected from the stocks. One group was placed in a white enameled pan, the other in a black enameled pan. Both pans were then placed under an illumination of 40 ft.-c. light intensity. Sixty minutes later, the average chromatophore stage of the isopods in each pan was determined and the backgrounds were interchanged with the result that the isopods which originally had been on a white background were on a black background and vice versa. The average chromatophore stage of the isopods in each pan was then determined 15 and 30 minutes after the backgrounds had been switched. The results of these observations are presented in Figure ID. As is evident, the black pigment of specimens on a black background dis- persed whereas the black pigment of specimens on a white background 30 O MINUTES Figure 1. Responses of melanophores of ldothea exotica to back- ground changes during the day (D) and night (N). Circles, from white to black. Dots, from black to white. 142 Tulane Studies in Zoology Vol. 3 concentrated. Adaptation of the melanophores of specimens placed on black and white backgrounds was complete in 15 to 30 minutes. The melanin of specimens on a black background became completely dispersed but was not completely concentrated on a white background. The existence of a daily rhythm of color change was suggested by the incomplete concentration of the melanin of specimens on the white background. Complete concentration of melanin of the blue crab, Callinectes sapidus, on a white background occurs at night only. Dur- ing the day a daily rhythm of pigment migration keeps the pigments dispersed (Fingerman, 1956a). On the other hand, the dwarf craw- fish, Cambarellus shufeldtii, does not exhibit a daily rhythm of pig- ment migration; the chromatophore pigments concentrate maximally during the day when specimens are placed on the appropriate back- grounds (Fingerman, 1956b). The experiment described above was performed, therefore, at night in order to determine if background adaptation is influenced by a daily rhythm of pigment migration. Twenty isopods were taken from the stock containers, divided into two equally sized groups, and placed on black and white backgrounds at 3:00 P.M. At 9:00 P.M. the average chromatophore index of the isopods in each pan was determined and the backgrounds were inter- changed. The results have been presented in Figure IN. The melanophore behavior at night was indicative of a 24-hour rhythm of color change. The melanin of specimens on both black and white backgrounds was less dispersed at night than during the day. However, the rates of pigment dispersion and concentration were the same during the day and night. Daily rhythm of color change. — The stock supply of isopods was placed in darkness at 5:00 P.M. The following morning at 7:00 A.M. specimens were selected from the stocks and divided into two lots of 12 individuals each. One group was placed in a white enameled pan, the other in a black enameled pan. Both pans were then placed under an illumination of 40 ft.-c. light intensity. The stock supply was not removed from darkness. Beginning at 8:00 A.M. and every two hours for the following 32 hours the average chromatophore index of 10 of the 12 individuals in each pan and of 10 in the stock supply was determined. If one of the 12 specimens in either the black or white pan was dead at the time the average chromatophore index was deter- mined the isopod was replaced with an individual from the stock supply. The specimen adapted to the background within the two hours prior to the next determination of the average chromatophore index. The procedure introduced no error and was valid in view of the rapidity with which the chromatophores adapt to black and white backgrounds ( fig. 1 ) . The results of observation of the melanophores are presented in Figure 2. A daily rhythm of melanin migration was evident in the three groups of Idothea. Idothea was darker during the day than at night. From the first observation at 8:00 A.M. until 6.00 P.M. of the same day the melanophores of the isopods in darkness and under No. 8 Fingerman: Melanopbores of Idotbea 143 constant illumination on the black background were equally dispersed. However, at night the melanin of specimens in constant darkness be- came more concentrated than the melanin of individuals on a black background under a constant illumination of 40 ft.-c. light intensity and remained more concentrated as long as the observations continued. Melanin of individuals on a white background was at no time as dis- persed as the pigment of individuals on a black background and in darkness. Each of the three groups of isopods was lightest in coloration about 11:00 P.M. and became darkest about 6:00 A.M. Obviously, the form of the daily rhythm was not symmetrical about noon and mid- night as are the vast majority of rhythms which are described in the literature. For example, the daily rhythm of migration of the distal bJ O < V) UJ a o i a. o r- < O a: x u •BLACK BACKGROUND ©DARKNESS O WHITE BACKGROUND I I L NOON MIDNIGHT NOON Figure 2. Daily rhythm of color change of Idothea. 144 Tulane Studies in Zoology Vol. 3 retinal pigment in the dwarf crawfish, Cambarellus shufeldtii, was symmetrical about noon and midnight (Fingerman and Lowe, 1956). Endocrine control of the melanophores. — The following experiments were designed to determine the sources and actions of the hormones which control chromatophoric pigment migration in Idothea exotica. The sinus glands and central nervous organs were the logical sites of hormone production in view of the results of McWhinnie and Sweeney (1955). The location and gross structure of the sinus glands and central nervous organs of Idothea exotica were the same as described for Oniscus asellus by Walker (1935) and in Trachelipus rathkei by McWhinnie and Sweeney (1955). Extracts of the sinus glands, thoracic nerve cord, and optic ganglia- cerebral ganglia-circumesophageal connectives complex were prepared. While the structures were under observation with a steroscopic dis- senting microscope, they were removed from isopods 17 to 25 mm long and placed in van Harreveld's solution. When the desired num- bers of each organ had been removed, they were transferred with a i ( - g 2 -O SINUS GLAND • CEREBRAL GANGLIA 9 THORACIC CORD O CONTROL J ! L 0 15 30 45 60 MINUTES Figure 3. Responses of the melanophores of Idothea exotica main- tained on a black background to extracts of sinus gland, central nervous organs, and saline as a control. Each point represents the average of 10 individuals. minimum of saline to glass mortars in which they were triturated. The organs were then resuspended in a sufficient volume of van Harreveld's solution so that the final concentration of extract was one-third of each organ in 0.02 ml of extract. Previous investigators have found that head extracts of Idothea bal- tica caused pigment concentration (Okay, 1945b). Suneson (1947) and Carstam and Suneson (1949) found that head extracts of Idothea neglecta also cause pigment concentration. Pigment dispersion fol- lowing concentration was noted in some of the experiments with Idothea neglecta. The first endocrinological experiments performed No. 8 Fingerman: Melanopbores of Idotbea 145 with Idothea exotica were designed, therefore, to investigate pigment concentration. At noon four lots of five isopods each were selected from the stock supply and placed on a black background under an illumination of 40 ft.-c. light intensity. Sixty minutes later the average chromatophore index of the isopods in each pan was determined and the melanin was found to be almost completely dispersed. The isopods in the four pans were injected respectively with extracts of sinus gland, cerebral ganglia complex, thoracic nerve cord, and van Harreveld's solution as a control. The average chromatophore stage of the isopods in each pan was then determined 15, 30, and 60 minutes after the extracts had been ad- ministered. The experiment was repeated once. No pigment con- centration was observed following injection of the extracts. Slight pigment dispersion was evident, however, although the magnitude of the dispersion was small because the pigment was almost completely dispersed prior to injection (fig. 3). In view of the results obtained with isopods whose pigment was dispersed, extracts were prepared as described above and injected into isopods whose pigment was almost fully concentrated. The pig- ment was obtained in a concentrated condition by placing the isopods on a white background and performing the experiment late in the afternoon, at which time the pigment tends to concentrate because of the daily rhythm. Five individuals were injected with each extract and five with van Harreveld's solution as a control. The experiment was repeated once. As is evident (fig. 4), each extract contained a hormone which caused melanin dispersion. No evidence of pigment concentration was evident 60 minutes after the injection of the extracts. u o $ u cr o i Q. O f- < O cc SINUS GLAND CEREBRAL GANGLIA THORACIC CORD CONTROL » _L 15 30 MINUTES 45 60 Figure 4. Responses of the melanophores of Idothea exotica main- tained on a white background to extracts of sinus gland, central nervous organs, and saline as a control. Each point represents the average of 10 individuals. 146 Tulane Studies in Zoology Vol. 3 Activity (potency) values of the tissue extracts and saline which had been injected into isopods with concentrated melanin were cal- culated in order to facilitate comparison of the extracts. The values were calculated by summing the average chromatophore indices de- termined 15, 30, and 60 minutes after the isopods had been injected. The product of three times the initial average chromatophore stage was then substracted from the respective sum for each group of iso- pods, because, if there had been no pigment activation, the sum of the average chromatophore stages which were determined 15, 30, and 60 minutes after the administration of the extracts would have been three times the initial average chromatophore stage. In order to ob- tain the true activity value for each extract the activity of the control group was subtracted from the values calculated for the three groups of isopods which had been injected with organ extracts. The order of melanin dispersing activity was: thoracic nerve cord (4.9 activity units) > cerebral ganglia complex (4.6 activity units) > sinus gland (2.1 activity units). Discussion The experiments showed only that direct injection of extracts failed to demonstrate the presence of a pigment-concentrating hormone and not that a pigment-concentrating hormone is lacking in Idotbea exotica. A similar situation in the fiddler carb Uca pugilator was noted by Sandeen (1950) who was able to demonstrate only a melanin-dispersing hormone. No direct endocrinological approach had shown the existence of a melanin-concentrating hormone although the existence of such a hormone had been postulated. Fingerman (1956c) demonstrated the existence of a melanin-concentrating hor- mone in Uca pugilator by bringing about rapid melanin concentra- tion in isolated legs which had been perfused with blood taken from specimens of Uca whose pigment was maximally concentrated and presumably maintained in the concentrated condition by a melanin- concentrating hormone. Chromatophore systems of isopods have proven to be as diverse physiologically as those of decapod crustaceans, concerning which an abundant literature has been accumulated. Some isopods produce a pigment-concentrating hormone only (Kleinholz, 1937; Okay, 1945a, b); another may be physiologically similar to ldothea exotica and pro- duce a pigment-dispersing hormone with no clear evidence of a con- centrating effect (Enami, 1941); and for still another there is con- clusive evidence for pigment-concentrating and dispersing hormones (McWhinnie and Sweeney, 1955). The daily rhythm of pigment migration in ldothea exotica per- sisted in darkness and under constant illumination on both black and white backgrounds. However, the pigmentary rhythm of Ligia baudiniana was apparent in individuals in constant darkness only (Kleinholz, 1937). Evidently the nature of the rhythmical mechanism differs in each of these two species. No. 8 Fingerman: Melanophores of Idotbea 147 Head extracts of each species of Idothea investigated have caused body lightening when injected into specimens of Idothea. However, Idothea exotica differs from all other species of Idothea which have been investigated. Contrary to other species of Idothea, extracts of endocrine sources of Idothea exotica caused body-darkening but not body-lightening. Evidently, among the species of a single genus of isopods the chromatophore systems may be extremely diverse. Summary and Conclusions 1. The melanophores of Idothea exotica, a coastal isopod, readily adapt to black and to white backgrounds. Individuals are lighter in color on a white background than on a black background. 2. A daily rhythm of melanin migration was observed in isopods maintained under constant illumination upon both black and white backgrounds and in constant darkness. Idothea is dark by day and light by night. 3. Extracts of sinus glands and central nervous organs injected into Idothea exotica caused pigment dispersion only. In all other species of Idothea which have been investigated conclusive evidence has been presented for a pigment-concentrating hormone but not for a dis- persing principle. 4. The physiological diversity of isopod chromatophore systems is discussed. References Cited Brown, Frank A., Jr. 1952. Hormones in crustaceans, in The Action of Hormones in Plants and Invertebrates. Academic Press, Inc., New York, N. Y. Carstam, Sven Ph. and Svante Suneson 1949. Pigment activation in Idothea neglecta and Leander adspersus. \Kungl. Fysiograf. Sallskapets Lund Forhandl., 19: 1-5. Enami, Masashi 1941. Melanophore responses in an isopod crusta- cean, Ligia exotica. II. Hormonal control of melanophores. Japan. Jour. Zool, 9: 515-531. Fingerman, Milton 1956a. The physiology of the black and red chromatophores of the blue crab, Callinectes sapidus. (in press.) 1956b. Endocrine control Of the red and white chromatophores of the dwarf crawfish, Cambarellus shufeldtii. (in press.) ____ 1956c. A black pigment concentrating factor in the fiddler crab, Uca. Science (in press). Fingerman, Milton and Mildred E. Lowe 1956. A daily rhythm in the regulation of the distal retinal pigment of the dwarf craw- fish, Cambarellus shufeldtii. (in press.) Gabe, M. M. 1952a. Histophysiol'ogie-sur 1'existence d'un cycle secre- toire dans la glande du sinus (organe pseudofrontal) chez Oniscus asellus L., C. R. Acad. ScL, 235: 900-902. 1952b. Histophysiologie-particularites histologiques de la glande du sinues et l'organe X (organe de Bellonci) chez Sphaeroma serratum Fabr., Ibid., 235: 973-975. 148 Tulane Studies in Zoology Vol. 3 Hogben, Lancelot T. and D. Slome 1931. The pigmentary effector system. VI. The dual character of endocrine coordination in amphibian colour change. Proc. Roy. Soc, Lond., B, 108: 10-53. Kleinholz, Lewis H. 1937. Studies in the pigmentary system of Crustacea. I. Color changes and diurnal rhythm in Ligia baudiniana, Biol. Bull., 72: 24-36. Matzdorff, C. 1883. Uber die Farbung von Idothea tricuspidata. Desm. Jena. Zeitschr. Naturwissen, 16: 1. McWhinnie, Mary Alice and H. M. Sweeney 1955. The demonstra- tion of two chromatophorotropically active substances in the land isopod, Trachelipus rathkei. Biol. Bull., 108 : 160-174. Menke, Heinrich 1911. Periodische Bewegung und ihr Zusammen- hang mit Licht und Stoffwechsel. Pflug. Archiv. fur Physiol., 140: 37-91. Nagano, T. 1949. Physiological studies on the pigmentary system of Crustacea. III. The color changes of an isopod Ligia exotica Roux. Sci. Repts. Tohoku Univ., 4th Ser. (Biology), 18: 167-175. Okay, Salahaddin 1945a. Sur l'excitabilite directe des chromato- phores, les changements periodiques de coloration et l'e centre chromatophortropique chez Sphaeroma serratum Fabr., Rev. Fac. Sci. Univ. Istanbul, Ser. B, 9: 1-21. 1945b. L'hormone de contraction des cellules pig- mentaires chez les isopodes. Ibid., 10: 116-132. PlERON, H. 1914. Recherches sur le compoi*tement chromatique des Invertebres et en particulier des Isopodes. Bull. sci. de la France et Belg., 48: 30. Sandeen, Muriel I. 1950. Chromatophorotropins in the central nervous system of Uca pugilator, with special reference to their origins and actions. Physiol. Zool., 23 : 337-352. Smith, H. G. 1938. The receptive mechanism of background re- sponses in the chromatic behavior of Crustacea. Proc. Roy. Soc, Lond., B, 125: 250-263. Suneson, Svante 1947. Colour changes and chromatophore activators in Idothea. Kungl. Fysiograf. Sallskapets Lund Forhandl., 17: 120-130. Tait, J. 1910. Colour changes in the isopod, Ligia oceanica. Jour. Physiol., 40 : xl-xli. Walker, R. 1935. The central nervous system of Oniscus. Jour. Comp. Neurol., 62 : 75-129. / // / f[eW \^v I&<* rt^j JIM ^®(DIL®OT Volume 3, Number 9 April 12, 1956 OSMOTIC BEHAVIOR AND BLEEDING OF THE OYSTER CRASSOSTREA VIRGINICA MILTON FINGERMAN and LAURENCE D. FAIRBANKS, DEPARTMENT OF ZOOLOGY, NEWCOHB COLLEGE, TULANE UNIVERSITY, NEW ORLEANS, LOUISIANA yus. com?, zoai L1B2MY APP2 7f95f aSiti'SnrJi KSBSiTY TULANE UNIVERSITY NEW ORLEANS TULANE STUDIES IN ZOOLOGY is devoted primarily to the 20ology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and con- tains an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Albert Collier, Chief, Gulf Fishery Investigations, United States Fish and Wildlife Service, Galveston, Texas VICTOR L. Loosanoff, Director, Marine Biological Laboratory, United States Fish and Wildlife Service, Milford, Con- necticut Thurlow C. Nelson, Professor of Zoology, Rutgers University, New Brunswick, New Jersey Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers or volumes may be purchased by individuals, but subscriptions are not accepted. Lists of papers published will be mailed on request. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers or volumes to the editor. Remittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zooh Price for this number: $0.50. George Henry Penn, Editor Meade Natural History Library, Tulane University, New Orleans, U. S. A. Assistant to the Editor: Don R. Boyer . APR 2 7 195 OSMOTIC BEHAVIOR AND BLEEDING OF THE OYSTER CRASSOSTREA VIRGINICA1 MILTON FINGERMAN and LAURENCE D. FAIRBANKS, Department of Zoology, Newcomb College, Tulane University, New Orleans, Louisiana The physiological processes required by aquatic molluscs to main- tain a constant internal environment are more complex in fresh water than marine species. The body fluids of fresh water molluscs are kept hypertonic to their environment by an active regulatory process, pri- marily salt absorption against the concentration gradient. For example, the osmotic pressure of the blood of Anodonta cygnea, a freshwater bivalve, is lower than the osmotic pressure of the blood of all marine molluscs studied and greater than the osmotic pressure of its fresh water environment (Schlieper, 1935). Within limits, the blood con- centration of A. cygnea remains more concentrated than its environ- ment as the salinity of its environment is increased (Florkin, 1938). On the other hand, marine molluscs are typically isotonic with their environment and poikilosmotic, as is characteristic of most marine invertebrates (Prosser et al., 1950). However, some marine molluscs are able to regulate their volume. Volume regulation is accomplished by the gain or loss of salts following an initial osmotic loss or gain of water. Molluscs unable to volume regulate will swell in hypotonic media and shrink in hypertonic media. The blood and pericardial fluid of the Japanese oyster, Ostrea cw- cumpicta, are hypertonic to the environment and the salinity of these fluids closely follows changes in the salt concentration of the environ- ment. The blood is more concentrated than the pericardial fluid (Yamazaki, 1929). The authors have learned through Dr. Thurlow C. Nelson that Dr. Imai of Japan is practically certain that the oyster referred to as Ostrea circumpicta by Yamazaki (1929) was actually Crassostrea nippona. The reason for believing the original name was incorrect is that Ostrea circumpicta is larviparous and belongs to the salt water flat type of oyster whereas Crassostrea nippona is oviparous. Nelson (1938) postulated that the genus Crassostrea which is armed with a superior cleansing mechanism, the promyal chamber, has in its evolution invaded the upstream zones of its environment in contrast to Ostrea which has remained in the sea or at least in waters of higher salinity. Crassostrea should, therefore, be a better osmoregulator than Ostrea. Cole (unpublished data) has shown that the clam Mercenaria 1 This study was conducted under a contract between Tulane University and the United States Fish and Wildlife Service. It was financed with funds made available under provisions of P. L. 466, 83rd Congress, approved July 1, 1954, commonly called the Saltonstall- Kennedy Act. 152 Tulane Studies in Zoology Vol. 3 has no power of osmoregulation and is limited to waters of salinity which do not fall below approximately 15 ppt for any considerable length of time. Hopkins (1936) showed that the initial effect of a rise or fall in salinity is to cause partial or complete adductor muscle contraction and slowing or cessation of water flow in Ostrea gigas. Adaptation of the adductor muscle and gill activities, as indicated by the openness of the valves and rate of pumping, was more rapid in response to increase in salinity than to decrease in salinity. Loosanoff (1952) demonstrated that as long as the valves of Crassostrea virginica re- mained open the changes in salinity of their shell and body fluids followed changes in salinity of the surrounding water. Stauber (1950) has shown that three distinct physiological varieties of Crassostrea virginica occur along the Atlantic Coast with critical spawning temperatures of 16.4°C in Long Island Sound, 20°C in the Bideford River, and 25 °C in Delaware Bay. The fact that Gulf Coast oysters "bleed" to a greater extent than .000 .010 1.020 SPEC. GRAV. 030 Figure 1. Freezing-point depression of sea water (SW) and oyster body fluid (BF) of various specific gravities. No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 153 Northern oysters is general information. Gulf Coast oysters may be, therefore, a fourth physiological variety. The present investigation was undertaken with a twofold purpose. The first aim was to obtain quantitative information concerning the weight changes and fluid losses that occur during the summer months in Southern oysters after the body has been removed from the shell. The second aim was to investigate in a detailed fashion the osmo- regulatory ability of the American oyster, Crassostrea virginica. Pre- liminary studies {e.g., Loosanoff, 1952) of the osmotic behavior of Crassostrea virginica have been performed but as yet no detailed in- formation is available. Materials and Methods Specimens of Crassostrea virginica used in these experiments were grown in the waters of Louisiana; the majority were from Barataria Bay. The oysters were maintained in large plexiglass aquaria containing water filtered through cotton, glass wool, and charcoal before being recirculated. The salinity of the sea water in the aquaria was main- tained at 17 ppt. Water with this salinity has a freezing-point de- pression of 0.88 °C. Distilled water was added to the aquaria to com- pensate for evaporation. The oysters were allowed to acclimate to the water in the aquaria for at least 24 hours before they were used in an experiment. The laboratory was airconditioned to assure that the temperature would not become lethal to the oysters. The water temperature was 18 °C when the experiments were initiated and gradually increased to 24°C by the termination of the experiments reported below. Specific gravities were determined by use of mixtures of chloro- form and benzene. A mixture of these liquids was prepared such that a droplet of the fluid whose specific gravity was to be determined would neither rise nor sink in the mixture but would remain at what- ever level it was placed. The specific gravity of this mixture was then determined by means of a hydrometer and was considered to be the specific gravity of the droplet. The specific gravities of the body fluids were determined at 24 °C and converted to the freezing-point depression at 15°C. Figure 1 was used in converting from the specific gravity to the freezing-point depression after the appropriate correction for room temperature was applied to the specific gravity value. The data of Figure 1 for sea water were taken from Zerbe and Taylor (1953). The data for body fluids were obtained experimentally. The highest specific gravity was obtained by adding salt to body fluid. The three lower specific gravity values were obtained by placing oysters overnight in aquaria which contained sea water of different salinities. The following morn- ing the body fluids of the oysters were collected and the specific gravities were determined. The freezing-point depressions of the body fluids with different specific gravities were then determined 154 f Tulane Studies in Zoology Vol. 3 with the aid of a cryoscope thermometer. The line relating specific gravity of body fluid to freezing-point depression is parallel to and 0.30 °C below that of sea water. This difference between sea water and body fluid was anticipated since freezing-point depression is a colligative property. The large protein molecules in body fluids have the same effect upon freezing-point as a chloride ion, for example, but have a greater effect upon specific gravity because of their large size. The method of determination of freezing-point depression from spe- cific gravity determinations allowed rapid determination of freezing- points with the result that more determinations could be run on a single day than would have been possible otherwise. In addition, the freezing-points could be determined with volumes too small for direct determination by standard cryoscopy. Experiments and Results Fluid and weight losses due to injury to the mantle and pericardium during shucking. — Eighteen oysters from each of eight lots, obtained on different dates, were shucked. In order to cause maximal fluid loss the mantle and pericardium were pierced while the oyster body was being removed from the shell. The bodies of the oysters were placed in individual, covered con- tainers after shucking and the initial body weight, including the fluids, was immediately determined. Fifteen, 30, 45, 60, 90 and 120 minutes following the initial determination of the weight, the weight of the body alone was determined. Before each of these weighings, the body was blotted to remove the external moisture. The results have been expressed as the percentage of the original weight of the intact oyster body including the fluids. The data for each group of 18 oysters are presented in Table 1 which includes the date each experiment was performed. The averages of the eight TABLE 1. Weight Changes of Oysters Shucked with Injury to the Mantle and Pericardium. Weights are Expressed as the Percentage of the Original Body Weight. Date Minutes after Shucking 0 15 30 45 60 90 120 May 27 100.0 57.5 53.5 51.5 50.0 50.0 49.5 June 2 100.0 67.8 64.3 63.0 61.7 60.7 59.7 June 9 100.0 57.0 51.0 50.0 49.0 47.0 45.0 June 19 100.0 70.0 65.0 63.0 62.0 61.0 60.0 June 22 100.0 61.5 60.0 59.0 58.0 57.5 57.0 June 28 100.0 48.0 44.0 43.0 41.0 41.0 40.0 July 12 100.0 67.0 63.0 61.0 60.0 59.0 57.0 July 17 100.0 55.0 50.0 48.0 47.0 45.0 44.0 Average 100.0 60.5 56.4 54.8 53.7 52.7 51.5 No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 155 60 MINUTES Figure 2. Weight changes of the body of oysters after shucking. The mantle and pericardium were intentionally ruptured during the shucking process. 30 60 MINUTES 90 120 Figure 3. Weight changes of the body of oysters shucked without injury to the mantle or underlying parts. 156 Tulane Studies in Zoology Vol. 3 experiments were used in the preparation of Figure 2. The greatest weight loss occurred during the first 15 minutes following the shuck- ing. The rate of fluid loss then decreased sharply. Fifty percent of the original body weight was lost after two hours. Fluid and weight losses following removal from the shell with no injury to the mantle. — Eleven oysters were shucked with a minimum of injury to the mantle and pericardium. The oyster shells were spread slightly. The adductor musle attachment was then carefully scraped away from each shell without putting the edge of the knife against the mantle. These oysters were placed in individual, covered containers and weighed in the manner described above at 0, 15, 30, 45, 60, 90, and 120 minutes from the time the oysters were removed from the shells. The results of this experiment have been presented in Figure 3. As is evident from a comparison of Figures 2 and 3, approximately 25 per cent more of the body weight was lost when the mantle and pericardium were pierced. The weight loss of the oysters with the intact mantles was probably due to fluid exuded from the sinuses in the mantle and from the cut adductor muscle. The over-all shape of the curves of Figures 2 and 3 was the same. After the large initial weight loss the slopes of the curves in Figures 2 and 3 were also the same. Similarity of both shape and slope after the initial loss of fluid indicated that the mechanism of fluid loss from 15 to 120 minutes was the same in all the oysters, whether the mantle was punctured or not. Weight losses induced by draining the free fluid betiveen the shells* — Wedges were placed between the shells of each of 10 oysters. While the shells were agape in the aquaria the oysters were allowed to close on wedges which prevented complete closure of the shells. These oysters were then removed from the aquaria. The water between the shells was shaken out and the shells were blotted. The oysters were kept on the table top for 120 minutes as were the controls and were weighed at the same time intervals as the controls. Prior to each weighing the fluid which had accumulated between the shells was discarded. After the weighing at 120 minutes the oysters were sacri- ficed. Their original body weight was then determined by subtracting the weight of the shells from the original total weight. The weight changes of these wedged oysters were expressed as the percentage of the original body weight and are presented in Figure 4B. A second group of 10 oysters was taken from the aquaria, blotted, and also kept on the table for the extent of the experiment. These oysters were weighed at the same time intervals as the controls and as the oysters with wedges. Prior to each weighing the shells were forced apart slightly and the free liquid shaken out. At the end of the experiment these oysters were also sacrificed and weighed. These weights were treated in the same fashion as the weights of the oysters that had been wedged open (Figure AC). As is evident from Figure 4, after 120 minutes the experimental No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 157 MINUTES Figure 4. Weight changes of oysters kept in air for 120 minutes. A, weight loss of oysters due only to evaporation of water from the shell. B, weight loss of oysters kept agape in air by means of a wedge; fluid which accumulated between the shells was discarded prior to each weighing. C, weight loss of oysters whose shells were forced apart in order to discard the accumulated free fluid prior to each weighing. Actual weights are expressed as the percentages of the original body weight. oysters had lost approximately 30 percent of their original body weight. The difference in weight loss between the oysters of Figure 4B and 4C was not significant. Ten oysters were taken from the stocks in the aquaria to serve as controls. The outer surfaces of their shells were blotted to remove the excess water. These oysters were then kept on the table top for two hours and were weighed at 0, 15, 30, 45, 60, 90, and 120 minutes after blotting. After the final weighing the oysters were sacrificed and the body weights including the fluids were determined. The weight losses due to evaporation from the outer surface of the shells were then expressed as a percentage of the original body weight. Although the loss of weight was due to loss of fluid from the shells and not the body, this method of expressing the data was employed because a small portion of the weight loss experienced by the experi- mental oysters was due to evaporation from the surface of the shell. However the major portion of the weight loss of the experimental oysters was due to fluid loss by the body of the oyster. The control oysters which had been kept on the table top for two hours, lost the equivalent of six percent of their original body weight by evaporation of water from the outer surface of their shells (Figure 4A). The oyster must be free to open and close its shell in a normal fashion in order to regulate its weight and consequently its volume. 158 Tulane Studies in Zoology Vol. 3 Disruption of the rhythmic opening and closing of the shells inter- fered with the ability of the oysters to volume regulate. Removal of the free liquid between the shells stimulated further secretion to replace this fluid at the expense of the internal body fluids. Weight losses of oysters drained of the free fluid between the shells and subsequently returned to the aquaria. — Ten oysters were wedged open in the manner described above and removed from the aquaria. The free fluid between the shells was then drained and the shells were blotted. The oysters were kept on the table top and weighed at 0, 15, 30, 45, 60, and 75 minutes after the free fluid had been drained from between the shells. The oysters with the wedges still between their shells were returned to the aquaria following the weighing at 75 minutes. The oysters were weighed at 15 minute intervals for 75 minutes after their return to the aquaria. Prior to each weighing of the oysters, which had been returned to the aquaria, their shells were blotted and the free fluid between the shells was drained. The free fluid of a second group of 10 oysters was drained by forcing the shells apart prior to each weighing. This group was also kept on the table top and weighed at the same intervals as were the wedged oysters. The non-wedged oysters were also returned to the aquaria after 75 minutes on the table top and were weighed for an additional 75 minutes. Both groups of oysters were sacrificed after the completion of the weighings. The original body weight was calculated by subtracting MINUT ES Figure 5. Weight loss of oysters whose shells had been wedged open (circles) or forced apart (dots) prior to each weighing. Both lots of oysters were kept out of water for the first 75 minutes of the experiment. Arrow shows when the oysters were returned to the aquaria. Free fluid between the shells was discarded prior to each weighing. No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 159 the weight of the shells from the original weight of the intact oyster. The weight changes, based on the original body weight, have been plotted in Figure 5. The circles represent the oysters which had been wedged open; the dots represent the oysters which had been forced open. The difference in weight loss between the two groups of oysters was not significant. Both groups of oysters continued to lose weight because of the removal of the free fluid after their return to sea water. A portion of the weight loss of oysters which had been forced open periodically may have been due to tearing of muscle fibers with concomitant injury to the blood spaces within the adductor muscle. A control group of oysters had been weighed and immediately re- turned to the aquaria for the duration of this experiment, i.e< 150 minutes. The control oysters experienced no weight change. This experiment also demonstrated that the oyster was unable to regulate its weight unless free to open and close its shell in the normally rhythmic fashion. Forcing the shells open at regular inter- vals or keeping the shells agape by means of a wedge prevented the oyster from regulating its weight and consequently its volume both in air and in sea water. Non-wedged oysters would open their shells and pump water in the aquaria. Weight changes of oyster wedged open in several concentrations of sea water. — Thirty oysters were wedged open, drained, blotted, and weighed in the manner described above. Ten of these oysters were 30 60 90 120 MINUTES Figure 6. Weight changes of oysters with a wedge between their their shells. A, oysters in sea water with a freezing-point depression (Ao) of 0.61° C; B, oysters in sea water with a freezing-point de- pression of 1.03° C; C, oysters in sea water with a freezing-point de- pression of 1.54° C. 160 Tulane Studies in Zoology Vol. 3 placed in an aquarium which contained sea water with a freezing- point depression (A0) of 0.61 °C, 10 in water with a freezing-point depression of 1.03 °C, and 10 in water with a freezing-point depression of 1.54°C. These oysters were also weighed at 15, 30, 45, 60, 90, and 120 minutes after having been placed in their respective aquaria. The weights have been converted to the percentage of the original body weight. The latter was determined by subtracting the weight of the shells from the original weight of the intact animal. The results have been plotted in Figure 6. Curve A represents the weight changes of the oysters wedged open in the most dilute sea water, A0 0.61; B, the weight changes in the intermediate salinity A0 1.03; and C, the weight changes in the most concentrated environment A0 1.54. The weight losses were directly proportional to the salinity of the environment. A simple osmotic phenomenon is the probable explanation of these results. This experiment led to the same con- clusion arrived at in the previously described experiments; to regulate its weight and volume the oyster must be free to open and close its shells in a normal fashion. Changes in the concentration of the combined mantle and peri- cardial fluids with changes in the salinity of the environment. — Four lots of 40 normal oysters each were taken from the stocks. A lot was placed in one of four concentrations of sea water. The freezing-point depressions of the sea water in each aquarium were (A0) 0.54, 1.26, 1.62, and 1.98°C. At 0, 2, 4, 6, 8, 10, and 12 hours after having been put into the respective aquaria, three oysters from each salinity were weighed and sacrificed. At the same time, three oysters from the stock supply were also weighed and sacrificed. The freezing-point depression of the water in the stock aquaria was 0.88 °C. The mantle and pericardium were punctured when the oysters were sacrificed and the escaping fluid was collected. This fluid was a mixture, therefore, of the pericardial and mantle fluids. The specific gravity of this mixture was then determined. The changes in salinity of the body fluid (A{) have been presented in Figure 7 for each of the salinities from which the oysters had been taken (A0). In the dilute medium the combined body fluids became diluted and in a con- centrated medium these body fluids became concentrated. These data indicate that the oysters did not osmoregulate but rather osmoadjusted. In Table 2 are listed the percentage weight changes of the oysters in this experiment. These percentages have been based on the oyster body plus the shell. These percentages would have been magnified approximately five times if calculated on the weights of the body without the shell. The weight changes of the oysters in all but the most concentrated sea water were, without doubt, insignificant. In the most concentrated sea water, if any weight change occurred one would expect the weight to decrease rather than increase. This weight increase must have been due to some phenomenon other than osmotic. Acting on the valid assumption that weight and volume No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 16 1 21 © © o 1.9 © ' o © 1.7 ■" 15 9 o © A, 1.3 © °C © """ © • © I.I ~h © e © ft -• • % 0.9 O o o Q A0 054 0.88 1.26 1.62 198 8 o • o 0.7 o o 0 0.5 _i_ . i .._. ' l • 1 1 8 12 HOURS Figure 7. The changes with time of the freezing-point depression of the combined mantle and pericardial fluids (Ai) of oysters main- tained in sea water of different salinities (Ao). vary directly with one another, one may conclude that the oysters showed a volume regulation at least in sea water with freezing-point depressions ranging from (A0) 0.54 to 1.62 °C and perhaps as high as 1.98°C. Since the density of the combined body fluids changed and the body weight was constant, the changes in freezing-point de- pression must have been due to transfer of salts and not water. The freezing-point depression values for the combined body fluids (A;) from the 2, 4, 6, 8, 10, and 12 hour determinations for each 162 Tulane Studies in Zoology Vol. 3 TABLE 2. Weight Changes of Oysters Maintained in Several Concentra- tions of Sea Water (ao). Weight Change is Expressed as the Percentage of the Original Weight. Weight of the Shell is Included in the Calculations. Hours Ao 0 100.0 2 4 6 8 10 12 0.54 100.0 99.5 99.6 99.6 99.8 99.9 0.88 100.0 99.6 99.8 100.7 100.2 99.7 99.7 1.26 100.0 99.4 99.7 99.5 100.0 100.2 100.2 1.62 100.0 100.3 99.9 100.1 100.1 100.1 100.1 1.98 100.0 101.5 100.8 100.6 101.4 101.5 100.5 environmental salinity (A0) were averaged and have been plotted against the environmental salinity (Figure 8). At the intermediate environmental salinities in the range of 20 ppt the salinity of the body fluids was relatively constant. The salinity in which the oysters were grown along the Louisiana coast is usually between 14 and 25 ppt. Obviously, the environmental salinities best for the production of oysters are the salinities in which the oyster is best able to regulate its salt content. Fractionation of the body fluids and osmoregulation. — Five lots of three oysters each taken from the stocks were placed in aquaria of 2.20 - Figure 8. Freezing-point depressions of combined mantle and pericardial fluids (A;) of oysters from several concentrations of sea water (Ao)« No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 163 graded salinities. The freezing-point depressions of the water in the respective aquaria were: 0.54, 1.17, 1.24, 1.62, and 1.98°C. After six hours all oysters from each salinity plus three oysters from the stocks were sacrificed. The freezing-point depression of the water in the stock aquaria was 0.88 °C. Instead of combining the body fluids as had been done in the experiment above, the body fluids were re- moved from the oysters in a manner that yielded four fractions. First, the shells were spread slightly and the free fluid between the shells was collected. Then, the adductor muscle was gently scraped from one of its attachments to the shell. This valve was removed. The mantle was then punctured and the mantle fluid was removed. The pericardium was pierced next and the pericardial fluid also collected. The fourth fraction was blood taken directly from the ventricle. The latter three fluids were collected in a syringe. The specific gravity of each fraction was determined for all the oysters. The values for each lot of three oysters were averaged. These data have been plotted in Figure 9. The salinity of the blood, the fluid most removed from the environment, was the most constant and the fluid between the shells, the fraction closest to the environment, was the least constant in its salinity. Obviously, the oyster has at least a limited ability to osmoregulate. The salinity of the blood tended to remain constant at the expense of the other body fluids. The data of Figure 9 have been replotted in Figure 10. In this latter figure the freezing-point depressions of each of the body fluids (Aj) has been plotted versus the environmental salinities (A0). Plot- ting the data in this fashion yielded additional information and facili- tated the discussion of the results. The fluid in the mantle of the oysters kept in the most dilute sea water was hypertonic to the other body fluids considered in this series of experiments. The high salinity of the fluid in the mantle was probably due to an active physiological process. Between the environmental freezing-point depressions of 0.54 and 1.17 °C the shell fluid was hypotonic to the other body fluids, but hypertonic to the environment. This hypertonicity was probably due to salt acquired from the mantle. In the dilute environment the pericardial fluid was hypotonic to the other internal body fluids. This hypotonicity was probably due to water removed from the blood by the nephridial organs and secreted into the pericardial cavity in an effort to maintain constant the salinity of the ventricular (arterial) fluid. The mantle was probably resistant to osmotic uptake of water from the environment because the mantle fluid was hypertonic to both the environment and the shell fluid when the oysters were in the extremely dilute medium (A0 0.54 °C). The lack of a significant loss of weight after 12 hours in the gradient of salinities (Table 2), showed that the oysters were able to volume regulate. The changes in the salt concentration of the body fluids were due to loss or gain of salt rather than water. The experiment was repeated twice in the same manner as described above with a change in exposure time only. Exposure times of four 164 Tulane Studies in Zoology Vol. 3 CO I m r r z T) > m z O * H £ o r rn <> ^ o -< — m > Figure 9. Freezing-point depressions of the body fluids (A>) of the oysters maintained in several concentrations of sea water. Body fluids were not mixed to allow determination of the freezing-point depressions of the fluids (1) between the shells, (2) in the cavities of the mantle, (3) within the pericardium, and (4) within the heart. and eight hours were used instead of the six hours of the first experi- ment. The results were essentially the same in the three experiments. The deeper in the oyster the fluid was obtained, the more constant was the freezing-point of the fluid. The difference between the lowest and highest freezing-point depressions with increased environ- mental salinity in the four hour experiment was: shell fluid, 0.58 °C; mantle fluid, 0.37 °C; pericardial fluid, 0.30 °C; blood, 0.15 °C The No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 165 150 140 1.30 120 A, °C 10 100 0.90 0.80 - - O SHELL • MANTLE O PERICARDIUM O HEART I 04 0 0.80 120 a:c 1.60 200 Figure 10. Relationship between the freezing-point depression of each fraction of the body fluids (Ai) and the salinity of the environ- ment (Ao). respective values for the eight hour experiment were: 0.44°C, 0.5 1°C, 0.30 °C, and 0.22 °C. Groivth of the oyster. — The oysters in the experiments described above were first and second year individuals. The combined weight of both shells has been plotted versus the number of individuals in each weight class (Figure 11). These values do not includes all the oysters used in these experiments because the weights of the shells of many of the oysters were not determined. The data form a bimodal curve. Each peak is probably due to the weights of the shells of in- dividuals in the two age classes. The body weights and shell weights of the oysters have been presented in Table 3. As is expected, as the shell weight increased, the body weight also increased. Discussion The major portion of the exuded fluids was lost through ruptures in the mantle and pericardium. Fluids may, however, also be lost through the cut edges of the adductor muscle. The latter structure receives arteries directly from the heart. The heart in turn receives blood from the lacunar spaces of the mantle. These spaces are usually filled with fluid. Contraction of muscle fibers in the mantle may 166 Tulane Studies in Zoology Vol. 3 90 - 75 -a v— O f -g CD 1 (0 o 1 f\) OJ ^ u; o> -4 CO (0 ro o ro o 00 o (0 o o o o o i o ■ i o o O — ° 3 i CO o o ro o o ro O ro ro O WEIGHT. GRAMS Figure 11. Combined weight of both valves of the oyster versus the number of individuals in each weight class. contribute to an additional loss of fluid by actively forcing out the mantle fluid. The limited osmoregulatory ability of the oyster Crassostrea vir- ginica was probably due in part to the ability of the mantle ( 1 ) to resist the osmotic influx of water when the oysters were in an en- vironment of low salinity and (2) to remain hypertonic to the other internal fluids in the upper and lower limits of the environmental salinity gradient used in these experiments. The nephridial organs probably also play a major role in osmoregulation ( 1 ) by removing salt from the fluid entering the arterial circulation when the animal is in a medium of high salinity and (2) by secreting a dilute urine when the animal is in an environment of low salinity. The osmoregulatory abilities of the American oyster, Crassostrea virginica, and the Japanese oyster, Crassostrea nippona appear to be distinct. The salinity of the blood in the Japanese oyster, unlike that of the American oyster, closely follows changes in the salinity of the environment (Yamazaki, 1929). The American oyster tends to main- tain the salinity of its blood constant at the expense of the other body fluids in spite of changes in the environmental salinity (Figures 9 and 10). The American oyster has evidently evolved a more efficient osmoregulatory ability than has been found in the Japanese oyster. No. 9 Fingerman and Fairbanks: Osmotic behavior of oysters 167 a Q to « U. O H s © 03 & CO W > « g < 3 w X H O m &. o a a a o Ei I fcuO 3 PQ o H I 1-1 o CO I o I co la co co o CO i CM cm o CM i CO 10 4J CO ».SP§ * J) H ^HNHlOHOOOOHHNOQOOO^t-lO t- HHNCqcOMMNOJH tH ©OOOOOOOOOOOOOOOi-Ii— I OOOOOOOOOOOtHOOiHtHOO OOOOOOOOtHOCNOTHiHiHiHcMO '*OOOOOOOCM^H(MTH'*-^eOiHiHT-l i-IOOOT-HOTHeONCOU500lfltMrHiHcM(N i-nOTHOTHTf-^ics«oci«Dci,>*©eoooT-i c-ooomoj'*ioiHomc-'*iH»HOOO eo riffllOt-COat-lOH^HOOOHO i-H © O CM CO CM ^HiHCMCMOt-IOOOOOOO ooooooooooooo OOOOOOHNWJlOffit-MOlOHN lOfflt-OOfflHHHHHHHHHHNNN i i I i i i i i i I I i i i i i i i T-lT-|l-l!-ll-lT-|!-lr-ll-4THT-lT-lT-ll-ll-|T-lT-lrH TJiU5(Ot-CCO)OH(MCO'>*lOtDt-COO)OH 1-H^HTHrHrH^HrHl-lrHiHCMCM 168 Tulane Studies in Zoology Vol. 3 Summary 1. Oysters which had been removed from their shells with no in- jury to the mantle and pericardium lost fluids equivalent to 26 per cent of their original body weight after 120 minutes. Most of this fluid loss occurred within 15 minutes after shucking. Puncturing the mantle and pericardium of shucked oysters resulted in a 50 per cent weight loss. 2. Oysters must be free to open and close their shells for weight and volume regulation. Oysters prevented from completely closing their shells lost weight both in and out of water due to secretion of body fluids. 3. Oysters have a limited ability to osmoregulate. The oysters tended to keep the salinity of their blood constant while the environ- mental salinity was altered. 4. The osmoregulatory abilities of an American and Japanese oyster are discussed. References Cited Florkin, Marcel 1938. Contributions a l'etude de l'osmoregulation chez les invertebres d'eau douce (1). Arch. Internat. de Physiol. 47: 113-124. Hopkins, A. E. 1936. Adaptation of the feeding mechanism of the oyster (Ostrea gigas) to changes in salinity. Bull. U. S. Bur. Fish. 48: 345-364. Loosanoff, Victor L. 1952. Behavior of oysters in water of low salinities. Nat. Shellfisheries Assoc, Convention Addresses, 1952. Nelson, Thurlow C. 1938. The feeding mechanism of the oyster. I. On the pallium and the branchial chambers of Ostrea virginica, O. ednlis, and O. angulata, with comparisons with other species of the genus. Jour. Morph. 63: 1-61. Prosser, C. Ladd, ed., 1950. Comparative Animal Physiology. W. B. Saunders Co., Philadelphia. Schlieper, C. 1935. Neuere Ergebnisse und Probleme aus dem Gebiet der Osmoregulation wasserlebender Tiere. Biol. Rev. 10 : 334-360. Stauber, Leslie A. 1950. The problem of physiological species with special reference to oysters and oyster drills. Ecology 31: 109-118. Yamazaki, M. 1929. On some physicochemical properties of the peri- cardial fluid and of the blood of the Japanese oyster, Ostrea cir- cumpicta, Pils. with reference to the change of milieu exterieur. Sci. Rept. Tohoku Imperial Univ., (4th ser.) Biol., 4(1, fasc. 2) : 286-314. Zerbe, W. B. and C. B. Taylor 1953. Sea water temperature and den- sity reduction tables. U. S. Coast and Geodetic Surv., Spec. Publ. No. 298: 1-21. I w » l / *-"*: A^.C '7 V3 a St ^®(DIL®@^ Volume 3, Number 10 June 22, 1956 ANATOMY OF THE EYESTALK OF THE WHITE SHRIMP, PENAEUS SETIFERUS (LINN. 1758) JOSEPH H. YOUNG, DEPARTMENT OF ZOOLOGY, TULANE UNIVERSITY, NEW ORLEANS, LOUISIANA ms. comp. zool lummy JUL 9 iw ■ TULANE UNIVERSITY NEW ORLEANS :tR. TULANE STUDIES IN ZOOLOGY is devoted primarily to the zoology of the waters and adjacent land areas of the Gulf of Mexico and the Caribbean Sea. Each number is issued separately and con- tains an individual study. As volumes are completed, title pages and tables of contents are distributed to institutions exchanging the entire series. Manuscripts submitted for publication are evaluated by the editor and by an editorial committee selected for each paper. Contributors need not be members of the Tulane University faculty. EDITORIAL COMMITTEE FOR THIS NUMBER Lipke B. Holthuis, Curator, Division of Crustacea, Rijksmuseum van Natuurlijke Historie, Leiden, THE NETHERLANDS. Robert E. Snodgrass, Collaborator, United States Department of Agriculture, Washington, D. C, U.S.A. Hermann Weber, Director, Zoologisches Institut der Univer- sitat Tubingen, Tubingen, GERMANY. Manuscripts should be submitted on good paper, as original type- written copy, double-spaced, and carefully corrected. Separate numbers or volumes may be purchased by individuals, but subscriptions are not accepted. Lists of papers published will be mailed on request. Authors may obtain copies for personal use at cost. Address all communications concerning exchanges, manuscripts, edi- torial matters, and orders for individual numbers or volumes to the editor. Remittances should be made payable to Tulane University. When citing this series authors are requested to use the following abbreviations: Tulane Stud. Zooh Price for this number: $0.50. Assistant to the Editor: Don R. Boyer George Henry Penn, Editor Meade Natural History Library, Tulane University, New Orleans, U. S. A. JUL 9 me •» ... ANATOMY OF THE EYESTALK OF THE WHITE SHRIMP, PENAEUS SETIFERUS (LINN. 1758) x JOSEPH H. YOUNG, Department of Zoology, Tulane University, New Orleans, Louisiana In some of the lower Crustacea and in many of the higher Crustacea the compound eyes are set upon movable stalks or peduncles. Their presence at the ends of extensions has excited speculation for many years. Carcinologists have long discussed the reasons for the eye- stalks, their similarity with the other appendages (Caiman, 1909), and the nature of vision in a stalked-eyed animal, among other things. Yet little has been written about the mechanics of the eyestalk with respect to vision. No one has proposed any useful explanation for the fine adjustments presumably available to a compound eye which has as numerous oculomotor muscles as the crustacean stalked eye. The presence of a set of muscles to move the corneal surface of the compound eye on the eyestalk, and of muscles to move the eyestalk about with respect to the body suggests the importance of the position of the corneal surface relative to the environment. By contrast, ad- justments of corneal position in an arthropod without eyestalks sug- gests a function of head and "neck" muscles for activities other than feeding, if we assume any importance to the arthropod of corneal position adjustments. Recently, the eyestalk nerves of a few crustaceans have been shown to contain neurosecretory elements which evidently proliferate hor- mone systems controlling such processes as molting (Passano, 1953), retinal pigment migration (Welsh, 1941), and chromatophore move- ments (Perkins, 1928). In view of the concentrated attention cur- rently being paid to matters of neuro-hormonal control of physiologi- cal functions in the arthropods, an understanding of the relation of vision to neurosecretion appears to be near at hand. The white shrimp, Penaeus setiferus, carries its eyestalks at an angle of about 75° to the median sagittal plane and at an angle of about ten to fifteen degrees to a frontal plane at the ocular plate (fig. 1). Only rarely are the eyes brought forward to lie in the optic depressions of the antennules, and then but for an instant for protection or possibly cleaning against the long plumules surrounding the depressions. Normally, therefore, in P. setiferus and many other species of shrimps, the eyes and stalks are widely spread and slightly upturned, a situation not understood by morphologists who, working with preserved materials, have described the eyestalks as projecting anteriorly (Cochran, 1935). Had previous workers taken into ac- 1 This study was supported by funds made available in the SaltonstalT-Kennedy Act, under a contract between Tulane University and the U. S. Fish and Wildlife Service. 172 Tulane Studies in Zoology Vol. 3 count the lateral position of the eyestalk in the shrimps, and for that matter in the crawfishes, a certain amount of confusion in the naming of eyestalk musculature might have been avoided. For in fact, medial muscles are anterior and lateral muscles are posterior. By way of uniformity, however, certain of the incorrect names are here employed. P. setiferus, an omnivorous scavenger like many shallow water and intertidal Crustacea, is a bottom feeder. According to an unpublished observation by Charles Dawson, of the University of Texas, schools of penaeid shrimps are frequently to be found on muddy bottoms. This worker describes placing several P. aztecus Ives 1891, in aquaria with an inch or two of mud on the bottom, into which the animals immediately burrow, except for the eyes. Such behavior suggests that the long eyestalks are among the organs enabling the penaeid shrimp to make use of mud for protection, especially after molting. In the past, observers have described square corneal facets in the eyes of several species of decapod crustaceans (Huxley, 1906; Caiman, 1909). A study of slides made of the corneal cuticle shows that the corneal facets in the compound eye of Penaeus setiferus are also square. Likewise the underlying ommatidial cells are square in P. setiferus and total four per ommatidium, as determined by the study of tangential sections of the eye from which the corneal cuticle had been removed. In longitudinal section the ommatidia of P. setiferus are seen to be similar to those of Astacus, with comparatively elon- gate crystalline cone and short rhabdom cells (Bernhards, 1916; Ramadan, 1952). A light pink substance which is thought to give the dark-adapted shrimp eye its bright pink color in strong lights is associated with the proximal or retinal pigment of the ommatidia. The ommatidial surface arises from a sclerotized cup, here named the optic calathus, or basket, to avoid confusion with the optic cup of the vertebrate embryo (fig. 1). The optic calathus rests upon the elongate stalk segment in a structural relationship permitting uni- versal movements, although the degree of movement varies in dif- ferent planes. Two points of articulation in the dorso-ventral plane allow the optic calathus considerable horizontal movement around the distal end of its supporting stalk. These dorso-ventral hinges are, however, suf- ficiently loose to permit vertical and rotational calathus movements, but to a lesser extent than horizontal movements. The long stalk is comprised externally of several longitudinal sclerotized bars which are separated by pliable cuticle. Two of the bars give support to the dorso-ventral points of articulation and others to less well-defined points of articulation between the stalk and calathus, and between the stalk and basal segment. The stalk is movable upon the short, box-like, basal segment in the horizontal plane. Vertical movements between the basal segment and the stalk are restricted. With respect to the structure here labelled No. 10 Young: Eyes talk of Penaeus setiferus 173 the median tubercle ( fig. 1 ) , it may be noted that the shrimps of the subfamily Penaeinae are said to have no distinct median tubercle on the ocular peduncle (Anderson and Lindner, 1943; Voss, 1955). However, many of the shrimps of this group do possess large, blunt, median tubercles, similar to those in Penaeus setiferus. Set between the basal segments is the ocular plate or lobe, a broad, roughly rectangular sclerotized structure which encloses laterally the medial parts of the basal segments (fig. 1). The ocular plate is the dorsal-most region of the protocephalon, a tagma about which more will be written later. Movements between the basal segment and the ocular plate are similar in extent to those between the stalk and the basal segment. Horizontal movements are limited to an arc of about fifteen or twenty degrees. Techniques The anatomical study of the eyestalks of Penaeus setiferus was made for the most part on white shrimp purchased alive from bait shrimp fishermen. The animals were fixed in Zenker's fluid, dehydrated to 70% ethyl alcohol and there stored. In spite of the difficulties in its use in the field, Zenker's fluid was found to have several advantages over formalin. Zenker's fluid softens or removes the calcareous de- posits and leaves the cuticle in a condition similar to thick cellophane. This mixture quickly penetrates to and fixes the internal organs, and in doing so prevents internal maceration caused by the post-mortem enzymatic activity of the hepato-pancreas. Formalin-fixed material is useless for the study of internal organs. The fixative greatly hardens the cuticle and the external muscles and fails to penetrate to the in- ternal organs. Dissections were performed under a stereomicroscope. Dissecting needles which were sharpened to fine points in mixtures of strong nitric acid and ethyl alcohol were employed. Locations of muscle attachments were verified on specimens of white shrimps cleared in strong alkali and stained in picro-fuchsin. The outlines of whole structures were used as templates within which muscles and other organs were sketched in layers on tracing paper as the dissections progressed. The tracings were transferred to drawing papers on a light box. The drawings were finished in ink and carbon pencil. Morphological Note For purposes of comparison the present work will have reference to the work of Berkeley (1928) on the "coon stripe" shrimp, Pandalus danae Stimpson 1857, to the works of Schmidt (1915) and Keim (1915) on Astacus astacus (Linn. 1758), to that of Welsh (1941) on Cambarus bartoni (Fabricius 1798) and to the work of Cochran (1935) on the blue crab, Callinectes sapidus Rathbun 1896. Of these animals, the white shrimp, Penaeus setiferus, appears to be the 174 Tulane Studies in Zoology Vol. 3 compound 'eye r os from op//c ca/a/nus-^ d'onsa/ arf/cu/a// of ca/a/hc an/enna/ sp'r?e^__. 6asa/ segment ommaf/d/a mecf/an /u&erc/e ,.opf/c j /a 'A ocu/ar p/a/e ^orh/fa/ an^/e carapace' ^ros/ra/ ' 5p/ne Figure 1. Penaeus setiferus. Dorsal view of eyestalks in anterior position. Rostrum cut away to show ocular plate. most generalized form, the modern species most like the generalized ancestral type. Protocephalon Muscles of Ocular Region Taking origin from either the epistomal invagination or the dorsal surface of the carapace and inserting upon basal parts of the eye- stalks are four pairs of muscles. The basal regions of the eyestalks will be assigned here to the dorsal part of that morphologically No. 10 Young: Eye stalk of Penaeus setijerus 175 separable pre-gnathal group of segments designated by Snodgrass ( 195 1 ) as the protocephalon. This simple head includes, in the order of their occurrence in the adult, the eyes, antennules, antennae, and labrum. The protocephalon is clearly distinct from the succeed- ing gnathal, thoracic, and abdominal tagmata, and in Penaeus setijerus, and other species of the genus (Grobben, 1917), is independently movable. Not shown in any of the accompanying plates is a pair of muscles which will be included in the present discussion, the tiny anterior protocephalon levator muscles, which are probably the muscles desig- nated by Grobben (1917) as the protocephalon levators in a Euro- pean penaeid. These muscles are difficult to make clear, either by dissection, or by illustration, since they take origin on the carapace, upon the nearly vertical sides of the rostral base. During removal of the carapace and the underlying layers of tough, fibrous epidermis and connective tissue, these muscles are torn away. The anterior protocephalon levators insert in the heavy connective tissue associated with the posterior edge of the protocephalon. Their actual levation of the protocephalon is negligible, since they are not only minute in cross section, but short in length. No counterpart of the anterior protocephalon levator muscles has been described for any of the species of decapod Crustacea referred to above, from which forms we must conclude that the muscles have been lost in the course of evolution. Posterior Protocephalon Levator Muscles (figs. 2, 3) The function of moving the protocephalon dorsally is performed by a pair of large muscles, the posterior protocephalon levator muscles, which originate close together at the dorsal midline of the carapace somewhat posterior to the origin of the anterior protocephalon levator muscles and which run forward and downward to attach on a nearly verticle transverse plate, posterior to the post-ocular region of the eyestalk base (fig. 3). The muscle inserts ventrally to the insertion of the anterior levators. The contraction of the posterior protocepha- lon levators may also act to rotate posteriorly the eyestalk base and hence raise the extended eyestalks. Possible homologues of the posterior protocephalon levator muscles are the median dorsal muscles designated as the musculus oculi basalis posterior. In Astacus, Schmidt (1915) found that these muscles arise on the median dorsal surface of the carapace and are attached by short tendons to the much longer tendons of other, more anteriorly- placed muscles, the musculus oculi basalis anterior. The anterior eye base muscles, to anglisize freely, are attached to the median dorsal region of the eyestalk base (Schmidt, 1915). More will be said of the latter muscles below. The posterior eye base muscles, it should be emphasized, do not attach to the eyestalk base in Astacus, but if the assumption is made 176 Tulane Studies in Zoology Vol. 3 opf/c j/af/C ocu/a/- pfafe basaf secp/venf oesophageal musc/es^ pai/er/or pro foe epha/on /ye^ ec/es/a/A atx/uc/or muscfe abrsa/ ca/a/huj re/rac/or musa'e^. '.cf/afn ro/a/o* musc/e. X~ Oraon .£•- /a/erai c a i a/hus ' / s/rac /o/ /nusc/e depressor ; sc/er'' I asa/ seamen/ /evafor musc/e ex/ema/ bar of an/ennu/ar foramen op/rc aanef/ von rC a/a /has rofa/ori rnusc/e j/enfra/ ca/at/ias refrcrc/or /77USC/& .jj, op h m a/m/c Drar?cf>es — - — op//c /ract ==*». o cu/ar p/a/e compressor ,r?usc/t'^ . 6ra/r> OCCj/ar p/a/e c/epresso/ musc/e pro'ocepha/on a'/rac/or musc/e ^ophfna/mc arfery Figure 4. Penaeus setifems. Dorsal view of left eyestalk. Dorsal muscles removed to show branches of nerves and arteries. depressor muscles "c," while small nonetheless depress the antennae. Although proof must wait upon a study of the nerves in Penaeus and Pandalus, Berkeley has homologized the so-called depressor muscles "c" of Pandalus and Astacus on the basis of their dorso-lateral origins on the carapace and their insertions on the medio-dorsal edge of the antennal basipodite (in Pandalus) and coxopodite (in Astacus). That the depressor muscles "c" in Pandalus and the protocephalon levators No. 10 Young: Eye stalk of Penaeus setiferus 181 in Penaeus are homologous seems fairly certain, in spite of the ap- parent change of insertion in the former. A review of cleared and stained exoskeletons of Pandalus might show multiple insertions of the muscle as in Penaeus. The homology of the protocephalon at- tractor muscles in Penaeus with the depressor muscles "c" in Astacus is less certain. In Callinectes, Cochran ( 1935) figures a pair of ocular attractor muscles which originate on the carapace. Their phylogenetic relation to the protocephalon attractor muscles in Penaeus is unlikely. Epistomal Stator Muscles (figs- 2, 3) Originating on the dorsal surface of the carapace, lateral to the posterior protocephalon levator muscles, and converging on the an- terior side of the epistomal invagination are a pair of small muscles which are named in the present work, the epistomal stator muscles (figs. 2, 3). The name derives from the fact that contractions of the muscles would appear to hold the epistomal invagination in position during the contraction of other muscles in the area. The epistomal stator muscles are homologous with the musculus oculi basalis posterior in Pandalus and Astacus and probably in Callinectes. Oesophageal Muscles (figs- 2, 3) The last of the muscles in the anterior region of the gnathothorax to be treated is a pair of oesophageal muscles (figs. 2, 3) which origi- nate on the antero-lateral surfaces of the carapace, dorsal to the pro- tocephalon attractor muscles, and converge upon the anterior surface of the oesophagus. They function to dilate the oesophagus. Dorsal oesophageal muscles are not shown in the works of Astacus, Panda- lus, or Callinectes, although Cochran (1935) figures several ventral oesophageal dilators in the latter form. Ocular Plate Muscles Arising in the ocular plate or post-ocular region dorsal to the brain are several pairs of muscles and a muscle group. Some of these muscles insert inside and some outside of the ocular plate. Ocular Plate Compressor Muscles (figs. 3,4) Attached about the shallow antero-dorsal groove of the ocular plate is a group of muscles which runs to the lateral wall of the ocular lobe (figs. 3, 4), the ocular plate compressor muscles. They function to draw the sides of the head lobe and ocular plate mesad, and to depress slightly the center of the ocular plate. Anterior Basal Segment Adductor Muscle (fig. 3) The anterior basal segment adductor muscle originates on the ocular plate dorsal to the brain and attaches to connective tissue and apodemal 182 Tulane Studies in Zoology Vol. 3 compound eye opf/C a an of ton c/orsaf cefafntta refractor : jc/e — w, 'aan f. /erferat ca/af/7U3 refractor musc/e.-- ocufomofor „-i- externa/ ba/- ot antennu/ar foramen— — z-^opifhaf/v/c *"" branches yenfra/ ca/arnus refractor rnusc/e _ _ b ra/n ^ cere bra/ £>/■ ■ ancn of ophft?at-mc arferu ** A f c/t cunToesopnaoeoi connect ve profocebnafon a/trocfar musc/e' ophfoo/m/c or/eru Figure 5. Penaeus setiferus. Dorsal view of left eyestalk. Dorsal muscles and optic tract removed to show ventral muscles and branches of nerves and arteries. material in the ventral part of the basal segment (fig. 3). Contrac- tions of the muscle turn the basal segment toward the ocular plate in a horizontal plane. Posterior Basal Segment Adductor Muscle (% 3) The posterior basal segment adductor muscle inserts in the basal No. 10 Young: Eyestalk of Penaeus setiferus 183 segment at the same point as the anterior basal segment adductors, but originates on the anterior side of the vertical transverse plate posterior to the post-ocular region (fig. 3). It, too, draws the an- terior edge of the basal segment toward the ocular plate. The origins of these muscles are so widely separated that we may conclude that they have never been the same muscle. How the basal segment ad- ductors may be homologized with the situation in Pandalus and Cal- linectes, in which forms no knowledge of muscle innervations exists, will be speculation. The ocular adductor muscles of Astacus and Pandalus may well be the homologues of the anterior adductor muscles of Penaeus, but hardly with the ocular adductors of Callinectes, in which animal the muscles are located in the distal end of the long stalk segment. Phylogenetic relationships of the posterior basal seg- ment adductor muscle are even more uncertain, although possibly it is the same muscle as the ocular attractor muscle in Pandalus and Astacus. The basal segment adductor muscles do not appear in Cal- linectes. Basal Segment Levator Muscle (fig. 3) The basal segment levator muscle originates at the antero-dorsal corner of the ocular plate and runs ventrally to the connective tissue and apodemal cuticle on the ventral surface of the basal segment (fig. 3). In the normal spread condition of the eyestalk, contraction of the muscle tends to raise the basal segment and with it the extended eyestalk. Basal Segment Muscles In the functional descriptions of the muscles which follow, the eye- stalks will be considered as if in their lifelike, lateral positions. Basal Segment Rotator Muscle (fig. 3) The basal segment rotator muscle is a short, broad structure origi- nating on the antero-dorsal edge of the basal segment and inserting on the antero-ventral edge of the same segment. Upon contraction, the muscle pulls the dorsal surface of the basal segment anteriorly, thus rotating the entire eyestalk forward. Eyestalk Depressor Muscle (fig. 3) Two very small muscles, the eyestalk depressor muscles, one slightly lateral to the other (fig. 3), function to draw the eyestalk ventrally. After a review of the literature, the present writer concludes that neither of these muscles, the basal segment rotator or the eyestalk depressor muscle, has been previously described. 184 Tulane Studies in Zoology Vol. 3 Eyestalk Muscles Eyestalk Abductor Muscle (% 3) All of the muscles of the eyestalk and optic calathus are associated with retraction and rotation of the optic calathus on the eyestalk, except for the long eyestalk abductor muscle (fig. 3). The proximal end of the eyestalk abductor muscle is attached in connective tissue in the ventral region of the basal segment. The muscle runs the length of the eyestalk to insert in connective tissue near the dorsal calathus retractor muscle. Contraction of the muscle swings the eyestalk hori- zontally to a lateral position. The eyestalk abductor muscle of Penaeus setiferus is very likely homologous with the abductor muscle described for Astacus and Pandalus, and possibly with the lateral branch of the ocular abductor muscle in Callinectes. Calathus Retractor Muscles The muscles in Penaeus setiferus which retract the optic calathus appear to be clearly represented by the retractor muscles of the eyes of Astacus, Cambarus, Pandalus, and Callinectes. Phylogenetically, the situation in Penaeus setiferus is somewhat more generalized than in the other forms which we are considering, in that several of the calathus retractor muscles in Penaeus have more than one part. In addition, Penaeus has a number of apparently independent rotator muscles, none of them previously described, which function to twist the optic calathus about a longitudinal axis through the eyestalk. Dorsal Calathus Retractor Muscle (figs. 3,4,5) The dorsal calathus retractor muscle arises in connective tissue near the ventral surface of the eyestalk and attaches to the dorsal edge of the calathus. Lateral Calathus Retractor Muscle (figs. 3,4,5,6) The lateral calathus retractor muscle, really the posterior retractor, originates on sclerotized material along the lateral, or actually posterior, blood sinus running the length of the eyestalk. The larger portion of this muscle attaches on the lateral edge of the calathus, the lesser part turning ventrally and running across the ventral edge of the calathus, just dorsal to the ventral retractor muscles ( fig. 6 ) . When this muscle contracts it not only retracts the calathus, but rotates the calathus about an axis longitudinal to the eyestalk. Ventral Calathus Retractor Muscle (% 6) The ventral calathus retractor muscle originates on several sclerotized regions on the ventral surface of the eyestalk. One part of the muscle is long and slender, while the others are short and arise from broad No. 10 Young: Eyestalk of Penaeus setiferus 185 comp Ye, cap///ary arbor \ J,/7 /L. fa/era/ ca/t refractor muse i e ocu/omotor **" nerves ex/erna/ cot o/ '??/*//fha//mc am Figure 6. Penaeus setiferus. Dorsal view of left eyestalk. Dorsal muscles and optic tract removed to show brain, branches of nerves, arterial capillary supply to distal optic ganglia, neurosecretory glands, and location of anterior eyestalk pore. origins (fig. 6). The muscle is inserted over a wide area on the ven- tral edge of the calathus. Medial Calathus Retractor Muscle (fig- 3) The medial calathus retractor muscle orignates on two points in 186 Tulane Studies in Zoology Vol. 3 the region of the median tubercle, and actually is comprised of two muscles ( fig. 3 ) • The larger muscle originates in the median tubercle and inserts in connective tissue dorsal to the distal optic ganglionic mass. The smaller muscle originates dorsal to the larger muscle, crosses over the optic tract beneath the larger muscle and inserts on a ventro-medial point on the calathus. The contraction of both muscles results in medial retraction of the calathus; functioning in opposition, the muscles retract the calathus in a vertical plane, reinforcing the action of the dorsal and ventral retractor muscles. Calathus Rotator Muscles (figs. 3, 4) At least three calathus rotator muscles may be seen in the eyestalk of Penaeus setiferus. Rotator muscles of this type have not been de- scribed for Pandalus, Astacus, Cambarus, or Callinectes. The calathus rotators bear a certain similarity to one another, in that they are all superficial in position and originate and insert in the heavy connec- tive tissue underlying the thick cuticle of the calathus. Eyestalk Vascular Supply (figs. 4, 5, 6, 7) Blood is pumped to the eyestalk in the vessel described by Huxley (1906) as the ophthalmic artery. From the anterior end of the heart, the ophthalmic artery runs forward dorsal to the gastric region, turns ventrally and laterally through dorso-lateral muscle origins to the protocephalon attractor muscle, with which muscle it enters the eye- stalk, giving off a large branch to the brain in passing. Once in the eyestalk, the artery runs medially along the optic tract and divides into several branches at the distal end of the eyestalk. The most proximal branch bifurcates on the dorsal surface of the optic tract (figs. 4, 7), sending a short vessel to and apparently through a small gland on the optic tract here designated as the X-Organ described by Hanstrom (1948) and about which more will be said below. A small part of the arterial branch to the gland continues proximally along the dorsal surface of the optic tract and has not been traced beyond the connective tissue of the basal segment. The larger part of the proximal ophthalmic branch runs distally into the distal optic gang- lionic mass (figs. 4, 7). Distally, the ophthalmic artery divides into two large branches, one of which (figs. 5, 6) carries blood into a highly-branched, dend- ritic structure embedded deeply among the optic ganglion cells (fig. 6). The organ has been named the capillary arbor, since it appears to distribute blood to ganglionic cells. Nothing similar has been found in the literature of the arthropod eye. The other, and most-distal ophthalmic branch, repeatedly divides to form a vascular plexus on the medial surface of the eyestalk, just beneath a heretofore undescribed pore to the exterior (figs. 6, 7). No. 10 Young: Eye stalk of Penaeus setiferus 187 The pore is designated as the anterior eyestalk pore. Its function is unknown. Circulation to the eyestalk of Penaeus setiferus, like that to some of the other appendages, is made up of a closed afferent system which is subdivided into capillaries in muscles, ganglia, and other organs. Venous returns of the blood to the heart is carried out in an open system, by means of sinuses in to the hemocoel. To what extent the closed-arterial, open-venous blood vascular system is representative of the Crustacea must wait upon further study (Caiman, 1909). Eyestalk Nerves (figs. 5, 6, 7) By far the largest nervous element in the eyestalk of Penaeus seti- ferus is the optic tract, a part of the brain, which rises from the antero- lateral region of the brain, runs distally in the eyestalk, increasing in diameter, and enters the calathus. Within the calathus the optic tract enlarges to incorporate the various distal optic ganglia and makes con- tact with the nerves from the ommatidia (figs. 6,1). If the distal optic ganglionic mass is pulled away from the dioptric elements of the eye, the tearing is confined to natural lines of weakness represent- ing a deep concavity. Lining the concavity so produced will be found the capillary arbor described above (fig. 6). Along the lateral side of the optic tract, and embedded in the perineurium in the proximal region of the optic tract, is a small nerve which branches out of the perineurium distal to the basal seg- ment. This nerve puts out several tiny branches to muscles and then enters a glandlike structure for which the name X-Organ (Hanstrom, 1948) is proposed (fig. 7). From the X-Organ a nerve continues along the optic tract distally to enter another, and larger, glandlike organ here termed the sinus gland (fig. 7). The sinus gland lies against and sends branches into the optic ganglionic mass at the distal end of the optic tract. It should be emphasized that the iden- tification of the X-Organ and the sinus gland is made on doubtful grounds, since no supporting histological or experimental evidence is presented. On the other hand, certain anatomical information lends support to the identification of the above-mentioned glandlike structures as the X-Organ and sinus gland. The support is to be found in the literature of neurosecretory experiments. The illustrations in some works of this literature are, to say the least, circumscribed (Passano, 1953), and useless to the morphologist. However, Welsh (1941) has taken pains to illustrate clearly his experiments on retinal pig- ment migration in Cambarus bartoni. From his figures, indicating careful anatomical work on the nerves of the eyestalk of C. bartoni, the locations and innervations of the X-Organ and the sinus gland appear to be similar to the glandlike structures in Penaeus setiferus. 188 Tulane Studies in Zoology Vol. 3 compound eyes op/ic acm