252 



S. J. Smith — Species of Pinnixa 

 Specimens JExaniined. 



No. 5 were all found in the tubes of AmpTiitrite ornata Verrill (Leidy sp.) 



Pinnixa Sayana stimpson. 



Pinnixa Sayana Stimpson, Annals Lyceum Nat. Hist. New York, vii, p. 236 (108), 



1860 (dese. of $ ; North Carolina). 

 Kingsley, Proc. Acad. Nat. Sci. Philadelphia, 1878, p. 323 (8), 1878. 

 Pinnixa cylindrica Smith, Invertebrate Animals of Vineyard Sound, Report U. S. 



Coram. Fish and Fisheries, part i, p. 546 (252), pi. 1, fig. 1, 1874 (Vineyard Sd. 



and Long I. Sd.) {Non Say sp. nee Stimpson). 

 1 Pinnixa sp. Faxon, Bulletin Mus. Comp. Zool. Cambridge, v, p. 263, pi. 4, figs. 



5-15, pi. 5, figs. 1-7, 1879 (early stages; Newport, Rhode Island). 



The carapax is narrower than in P. chcetopterana, bnt still nearly, 

 or even somewhat more than, twice as broad as long. There is a 

 tuberculose ridge along the anterior inferior margin as in P. chcetop- 

 terana, and above and nearly parallel with it a sharp denticulated 

 carina extending from the base of third ambulatory leg across the 

 branchial region and across the cervical suture to the hepatic 

 region, being most conspicuous at the cervical siiture, and separating 

 the dorsal from the nearly perpendicular antero-lateral ))orfler of the 

 carapax. In the female there is no carina on the cardiac region, 

 only an obtusely angular ridge sejoarating the flat dorsal from the 

 inclined posterior dorsal region ; while in the male (as already 

 described by Stimpson) the ridge is marked l)y a very slender, but 

 acute, carina not interrupted in the middle. 



The chelipeds in the one male examined are unequal, the smaller 

 being in all respects like the chelipeds of the female, while the other 

 (apparently of the normal form for the male) is very much as in the 

 male P. chcetopterana, though apparently a little smaller in propor- 

 tion. The tooth near the base of the digital portion of the propodus 

 is inconspicuous but still clearly discernible. 



The first and second pairs of ambulatory legs are long and very 

 slender, the first pair being longer than the chelipeds, and the second 

 considerably longer than the breadth of the carapax. The third pair 

 are only a little longer than the second and proportionally consider- 



