V. Ox THE SPECIES OF PiNNIXA INHABITING THE NeW EnGLAND 



Coast, with remarks on their early stages. By S. I. Smith. 



In tlie Report of the U, S. Commissioner of Fish and Fisheries for 

 1871-2, I have figured a species of Pinnixa and recorded its occur- 

 rence in Vineyard and Long Island Sounds, but referred it incorrectly 

 to P. cylindriea (Say sp.) At that time I had examined only three 

 specimens, and all of them were of the species figured. In 1874 and 

 1875 additional specimens of Pinnixa were collected by Fish Com- 

 mission parties in Fisher's Island Sound, Vineyard Sound, and Buz- 

 zard's Bay, but I did not examine them carefully, supposing the 

 specimens to be of the same species as those previously examined. 

 During these seasons, however, I had some opportunities for studying 

 the early stages of the genus. 



In 1874 zoese of Pinnixa were obtained in abundance from the 

 eggs, but I was not able to rear them to later stages. In 1875 zoeae 

 were again obtained from the eggs and many zoete in later stages 

 were taken at the surface. Among those obtained at the surface 

 there were two forms which at first sight looked like two stages of 

 the same species, but on closer examination, they both appeared, judg- 

 ing from the advanced condition of the cephalothoracic and abdomi- 

 nal legs, to be in the last zoea-stage. The larger and much the more 

 abundant of these two forms, the one designated in my notes as the 

 "long-spined zoea," agrees with the zoea of Pinnixa, from Newport, 

 Rhode Island, figured by Mr. Faxon (Bull. Mus. Comp. Zool., vol. v, 

 plate 4, figs. 5-15, 1879). The other form, designated in my notes 

 as the " short-spined zoea," is considerably smaller and has very much 

 shorter dorsal and rostral spines, even proportionally shorter than in 

 the first stage of the zoea of Pinnixa c/uMopterana figured by Mr. 

 Faxon (plate 4, fig. 1), so tliat the distance from the tip of the dorsal 

 to the tip of the rostral spine is only about half as great as in the long- 

 spined form. Except in these characters I was unable to find any 

 differences wiiatever and, though then aware of the occurrence of one 

 species only on the New England coast, I supposed that the forms 

 represented two species of Pinnixa. 



