XIV. REPORT ON THE MARINE ISOPODA OF NEW ENGLAND AND 



ADJACENT WATERS. 



BY OSCAR UARGER. 



The following paper includes the species of Isopoda at present known 

 to inhabit the coast of New England and the adjacent regions, as far as 

 Nova Scotia on the north and New Jersey on the south. These limits 

 have been chosen from the fact that nearly all the marine collections of 

 this order made by the Fish Commission have been from the New Eng- 

 land coast, except those from the Nova Scotia coast in 1877, while the 

 commission had its headquarters at Halifax. Previous to the work of 

 the Fish Commission extensive collections had also been made, mostly by 

 Professors A. E. Yerrill and S. I. Smith, of Yale College, in the Bay of 

 Fundy and at other places along the coast as far south as Great Egg Har- 

 bor, in the southern part of New Jersey. The collections thus obtained, 

 and others in the museum of Yale College, have, through the kindness of 

 Professor Yerrill, been used in the preparation of this article. As there 

 has not yet been sufficient opportunity for the study of the Bopi/ridce, 

 only a list of the known species of that family is included, and for this I 

 am indebted to Professor S. I. Smith. The species of the remaining fam- 

 ilies are described at length, and nearly all figured in more or less detail 

 in the plates accompanying the article. Throughout the article especial 

 reference will be had to the Isopoda of our own coast, and many pecu- 

 liarities of structure, not found in our genera, will be more or less com- 

 pletely disregarded. As the Oniscidce are a terrestrial family, only a few 

 species, found usually, or only, along the shore are here included. 



ISOPODA. 



This group is an order of Crustacea, so named from two Greek words, 

 "<ro<r, equal, and TTU<?, a foot, from the general similarity of the legs 

 throughout, all being thoracic. The order belongs to the Tetradeca/poda, 

 11 fourteen-footed," called also Edriophthalma, or " sessile-eyed" Crustacea. 

 All of these terms, however, require modification when applied to the 

 animals included in this order, since in the genus Astacilla the anterior 

 pairs of legs are quite unlike the posterior, in Gnathia there are never 

 more than twelve feet, or legs, in six pairs, and lastly in Tanais and its 

 allies the eyes, when present, are not sessile, but articulated with the head, 



or stalked, as in the higher Crustacea. It may, however, be stated that 



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