MUSEUM OF COMPARATIVE ZOOLOGY. 137 



below there is a strong, triangular, pyramidal spine, nearly as large as 

 the dorsal spines of the carapax ; margins of the meros crenulated w ith 

 six or seven small teeth on either edge; carpus flattened above, with two 

 strong, crenulated crests, the outer one of which bears a larger, spini- 

 form tooth at the middle ; hand with an elevated, nine-toothed superior crest 

 and eleven-toothed outer margin ; fingers very small ; dactylus at right 

 angles with palm. Ambulatory feet much compressed ; antepenult and 

 penult joints with a laminiform crest above ; meros-joint of the posterior 

 pair with a slight crest below. Abdomen glabrous. 



Of this species there is but one specimen — a female — in the collec- 

 tion ; in which the length of the carapax is 0.32 ; the breadth, 0.39 inch. 

 The length of the hand is 0.28 inch. 



The specimen was taken in 11 fathoms, four miles southwest of Logger- 

 head Key. 



Subfamily CRYPTOPODIINAE. 



Cryptopodia concava nov. sp. 



Carapax subpentagonal, greatly expanded posteriorly, the posterior 

 margin, which is nearly straight, equalling the entire width; lateral 

 margins short; antero-lateral margins slightly convex. Rostrum trian- 

 gular. The gastric region is protuberant, and from its summit a sharp, 

 crenulated ridge or raised line passes on either side to the postero-lateral 

 angle, enclosing a concave, triangular space. The surface between this 

 ridge and the antero-lateral margin is also concave. The entire upper 

 surface of the carapax, the ridges excepted, is smooth and shining. The 

 margins are crenulated with small teeth, the furrows separating which 

 extend for some little distance inward, giving the indentations the appear- 

 ance of being much deeper than they really are. The teeth themselves 

 are minutely granulated. External maxillipeds smooth, glabrous ; meros- 

 joint triangular, with the external angle very acutely projecting, and the 

 internal angle without a notch for the insertion of the palpus, the first 

 joint of which is indurated, with a projecting tooth at its extremity. 



Chelipeds flattened as in C. fornicata, but with the meros-joint nar- 

 rower, the'earpus smaller, and the hand convex below; fingers slender, 

 curved. Ambulatory feet crested; crest of meros spinulose above and 

 below. Transverse crest of sternum bilobed, each lobe being three- 

 toothed, and in the same line with a tooth on the basal joint of the 

 cheliped, which belongs also to this crest, which forms the margin of the 

 concave and perpendicular front of the sternum. 



The dimensions of the only specimen found — a young female — are as 

 follows: Length of carapax, 0.32; breadth, 0.43; proportion, 1 : 1.34; 



