THE CANCROID CRABS OF AMERICA 129 



Callinectes cayennensis A. Milne Edwards, Crust. Reg. Mex., 1879, p. 226 (var. 

 of C. diacanthus) (type-locality, Guiana; 2 male cotypes in Paris Mus.). 



Diagnosis. — Antero-lateral region smooth, non-granulate. Lateral 

 spine less than twice as long as preceding tooth. Male abdominal 

 appendages as long as abdomen. Six prominent bosses at middle of 

 carapace. Frontal teeth typically broadly rounded. 



Description. — Carapace very convex; deeply furrowed about the 

 middle ; two prominent bosses at inner angle of each branchial region ; 

 a deep median cardiac groove; surface coarsely granulate, except along 

 the lateral margin and on the hepatic region, where the carapace is 

 smooth. Intramedial region very long, length about equal to posterior 

 width and barely half of anterior width. Front with four large, 

 bluntly rounded teeth, the median pair the smaller and a little less 

 advanced than or quite as advanced as, the lateral pair. Suborbital 

 tooth short, triangular, narrow, obtuse. Antero-lateral teeth broad, 

 triangular, their posterior margins a little longer than the anterior, 

 tips acute, the last two or three teeth spiniform. Lateral spine short, 

 usually less than twice the length of the preceding tooth. Costae of 

 chelipeds rough with depressed granules, often appearing almost 

 smooth to the naked eye.' Outer distal spine of merus and carpus 

 usually normal, though sometimes in old specimens reduced to blunt 

 projections. A short stout tooth or spine on anterior margin of 

 carpus just below inner angle. Penultimate segment of male abdo- 

 men constricted in its proximal portion, widening at both extremities; 

 terminal segment long; appendages reaching to end of abdomen, and 

 doubly curved, tips crossing. The sternum has a deep longitudinal 

 groove in front of abdomen. Abdomen of female very long, especially 

 the penult segment; terminal segment longer than wide. 



Color. — The carapace may be variegated with green, yellow, red, 

 brown, and blue, spotted with yellow or red; chelipeds purplish brown. 



Measurements .—yiaXe (18234), total length of carapace 74, width of 

 same 140, width at anterior base of lateral spine 121.8, fronto-orbital 

 width 59.8, width of front 21 mm. 



Variety. — Occasional specimens (42852 and 43913) present a strik- 

 ing variation from type in the form of the marginal teeth of the 

 carapace. Those of the front are triangular, and pointed instead of 

 rounded at tip, approaching exasperatus; those of the sides are much 

 shallower than in true hocourti and have rapidly convergent margins 

 and narrow spiniform tips, resembling sapidus; in other respects the 

 specimens are typical. 



Range. — West Indies to State of Santa Catharina, Brazil. 



Material examined. — 



JAMAICA.— 1928, C. R. Orcutt; 1 female (61340). Montego Bay; 

 caught in seine near shore; June 24, 1910; C. B. Wilson, 1 male, 

 variety (42852). 



79856—30 10 



