236 Ifotes on North American Crustacea. 



front, but marked by no ridges. Chelipeds robust. Hand large in 

 the male ; palmar edge perpendicular ; fingers strongly gaping ; poUex 

 very short, but acutely prominent and curved, with a tooth on its inner 

 margin next the base of the dactylus ; dactylus strongly hooked, smooth 

 on both margins. In the female, fingers much compressed, not gaping, 

 broad and oblique ; pollex nearly as long as the dactylus, and armed 

 with a tooth on the middle of its inner margin. Ambulatory feet stout, 

 hairy, with a very short dactylus. Feet of the penult pair very much 

 longer and stouter than the others, with a transverse groove next the 

 summit of themeros; carpus and penult joint crested above; inferior, 

 margin of meros and penult joint denticulated ; inferior surface thickly 

 pubescent. Length of the carapax in a male at the middle, 0.19 ; 

 breadth, 0.61 inch. Females are generally larger. 



Found in the tubes of Chaetopterus pergamentaceus^ on the 

 muddy or clayey shores of Charleston Harbor, S. C. 



Pinnixa sayana, nov. sp. 



Carapax smooth, glabrous, depressed at the middle, and with a slight 

 sharp transverse ridge parallel with and near to the posterior margin, 

 not interrupted at the middle. Two similar ridges on the antero-lateral 

 slope, distant but nearly parallel with each other, the superior one 

 curving inward and defining the branchial region. External antennae 

 about one-third the length of the carapax. Hands robust, compressed, 

 scarce twice as long as broad, smooth, and of the monodactyle kind, 

 the pollex being very short ; dactylus curved to a right angle. No teeth 

 on these fingers. Ambulatory feet smooth, rather slender, with dactyli 

 rather long ; penult pair larger than the others, but proportionally 

 much less robust than in other species of the genus. Length of carapax 

 in a male, 0.125 ; breadth, 0.24 inch. 



This species approaches nearer to P. monodactylus Say, 

 than any other species yet described, but it does not have the 

 long antennae and the teeth at the base of the fingers men- 

 tioned in Say's description. The carapax in our species is 



