2o6 



The carapace is almost semi-cylindrical longitudinally, but completely straight in transverse direction. 

 The various regions are scarcely to be made out, but there is some indication of a cervical 

 groove, situated far behind, and traces of gastro-hepatic and branchio-hepatic sulci. 



The front is perpendicularly defiexed, its free edge is perfectly truncate (fig. i a) 

 and the lateral angles rounded, subrectangular. Supra-orbital margin transverse. Orbit shallow, 

 small; eye-stalk piriform, very thick in the middle; the small eye with its light brown pigment 

 is lying at the ventral side of the tip of the ocular peduncle. In the specimen measured by 

 Miss Rathbun the fronto-orbital distance is exactly one-half the greatest width of the carapace, 

 but in my specimens this distance is usually somewhat larger. The antero-lateral margins, of 

 the carapace are i7„ times as long as the postero-lateral ones, entire and conspicuously divergent 

 backward, so that the ratio of length of carapace to greatest width is i : 1.6, much greater 

 than in the preceding species. At the level of the greatest breadth the lateral margins are 

 much less sharply defined and convergent backward, in an individually varying degree: in the 

 adult cf and in some small 9 this convergency is much more marked than in other individuals, 

 so that in the former group the convex posterior margin of the carapace is proportionately 

 .shorter than in the second group. 



Antennules transversely folded beneath the front; antennae short, scarcely outreaching 

 the width of the orbit. Epistome distinct, vertical, its free edge straight. Lateral margins of 

 buccal cavity parallel. External maxillipeds smooth and glossy (fig. 1 1^), antero-e.xternal angle 

 of merus conspicuously produced outward and forward ; exognath more than one-half as broad 

 as ischium, thick, vaulted transversely. 



Chelipeds markedly unequal in the apparently adult cT (the left being much the larger), 

 in the remaining examples they are equal in size. Meropodite short, inner and upper border 

 unarmed, but hairy; carpopodite broader than long, inner angle sharply produced, hairy; chelae 

 (fig. I c, d) entirely smooth and bare, save for some sparse hairs along the borders of smaller 

 chela; palm carinate at upper border, especially proximally, and with a longitudinal, low keel 

 running very near the under border; fingers compressed, crenulate at inner margins, the crenulations 

 being much less pronounced in the adult cf (here figured) than in the other individuals, both 

 fingers, especially the fixed one, of a lighter colour than the palm, which must perhaps be 

 ascribed to their original colour (red?) having disappeared in alcohol preservation. 



Walking legs of the same build as in C. ciliata, but much less hairy. Meropodites 

 slender, nearly naked, but with some hairs at the distal end of the posterior margin. Dactyli 

 of first pair straight, those of second and third pair very faintly curved, in last pair curved 

 backward and upward. 



Abdomen of cf (fig. \e) very narrow, the first segment, that is almost linear, scarcely 

 measuring one-third of the breadth of the last segment of the sternum; the third segment 

 is very little projecting outward, so that its lateral angles are right. 



This species with its relatively broad and very shining carapace is easily recognizable; 

 it is most nearly related to C. fulgida Rathbun, from which it is, however distinguished by 

 differences, enumerated by Miss R.\thbun and also partly mentioned in the key to the genus, 

 given a few pages before. 



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