98 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



Genus CALLINECTES Stimpson 



Callinectes Stimpson, Ami. Lye. Nat. Hist. New York, vol. 7, 1860, p. 220 [92]; 

 type, C. diacanthus (Latreille) = C. sapidus Rathbun. 



Differs from Portunus in having the abdomen of the male very- 

 narrow, X-shaped, and the merus of the outer maxillipeds strongly 

 produced outwardl}^ at the antero-extemal angle. The different 

 species agree also in being of large size; in having only four dorsal 

 carinae, formed of single granules; two transverse, usually curved and 

 subparallel lines on the gastric region and one sinuous obhque line 

 on the branchial region leading inward from the lateral spine; eight 

 strong antero-lateral teeth followed by a stout spine at the lateral 

 angle; stout chelipeds, the manus with five external carinae, a supero- 

 distal spine and a proximal spine at articulation with carpus; the 

 carpus without an inner spine, an outer spine at widest part of article; 

 merus with three (exceptionally 4) stout spines on inner margin and 

 a small spine at postero-distal end; paddles without spines. Maxi- 

 mum size of female less than that of male; abdomen of immature 

 female triangular from fourth segment to extremity. 



Inhabits the shores of tropical and temperate America; West Africa ; 

 South Pacific islands. 



KEY TO THE AMERICAN SPECIES OF THE GENUS CALLINECTES 



A'. Front bidentate between the teeth at inner end of orbits. Appendages of 



male abdomen reach end of terminal segment sapidus, p. 99. 



A^. Front quadridentate between the teeth at inner end of orbits. 

 B'. Median pair of frontal teeth low, rudimentary. 

 C Inner orbital fissure closed. 



D'. Appendages of male abdomen reach end of terminal segment. 

 Antero-lateral teeth acuminate. Intramedial area^* about 



twice as broad as long sapidus acutidens, p. 111. 



D^. Appendages of male abdomen do not reach beyond middle of 

 penult segment. Antero-lateral teeth broad and shallow. 

 Intramedial area about three times as broad as long. 



ornatus, p. 114. 

 O. Inner orbital fissure open. Appendages of male abdomen reach only 



to distal fourth of penultimate segment bellicosus, p. 112. 



B'^. Median pair of frontal teeth well developed, even if small. 



C Lateral spine of carapace more than twice length of posterior margin 

 of preceding tooth. 

 D'. Intramedial region shorter than its posterior width. 



E'. Second to sixth antero-lateral teeth with anterior and pos- 

 terior margins subequal. Tips of male appendages 

 straight, reaching terminal fourth of penultimate segment. 



danae, p. 118. 

 E^. Second to fifth or sixth antero-lateral teeth trending for- 

 ward, their posterior margins convex and longer than 

 anterior margins. 



" That part of the gastric region behind the posterior of the gastric carinae. 



