68 Notes on North American Crustacea. 



bulatory feet curved, of nearly equal and moderate length ; those of tlie 

 last pair long. 



Inhabits the coast of So^^th Carolina. 



Pinnixa cylindrica. 



Pinnotheres cylindricum, Say; Jour. A. N. S., Philad. i. 452. 

 Pinnixa cylindrica, White; An. & Mag. Nat. Hist., xviii. 17Y. 

 M.-Edwards; Mel. Carcin., 186. 



The male of this species differs considerably from the female, 

 in its broader carapax, which is depressed or concave at the 

 middle ; — the hand is also broader, with nearly transverse fingers, 

 and the dactylus curved, without a median tooth. These cha- 

 racters accord nearly with Say's description of his P. mono- 

 dactylum. The superior edge of the meros-joint of the feet is 

 smooth, except near the outer extremity, in all the female spe- 

 cimens of this species which have come under my notice, 

 although it is stated by Say to be granulated. The palpus of 

 the outer maxillipeds in this and the following species, is large, 

 with the dactylus attached to the penult joint near the base of 

 the latter, as in Pinnotheres, and not near its extremity as in 

 Pinnixa transver salts, Lucas. 



Say remarks that P. cylindrica is probably not parasitic. It 

 is so however, although, as might be judged from the hardness 

 of its carapax, it never revels like the Pinnotheres among the 

 soft folds of the bivalve mollusca. It lives in the tube of a 

 rougher host, — the Chmtopterus, a large worm found on the 

 coast of South Carolina, whose parchment-like sheath, expanded 

 at the middle, is bent in the form of a semicircle, so that both 

 extremities project to the surface of the mud. 



Pinnixa laBvigata, nov. sp. 



Body glabrous above and below, particularly in the female. Carapax 



