346 REPORT- OP COMMISSIONER OF FISH AND FISHERIES. 



c6te\" No species of Idotea that I have seen has the second segment 

 of the pleon composed of two segments, united along the back but sepa- 

 rated by an incision at the sides, as described in the parenthesis above, 

 and two certainly of the other species included by Edwards in the sec- 

 tion with I. tricuspidata agree with it in the structure of the pleon as 

 described in 1. irrorata. Meinert unites this species with I. pelagica 

 Leach under the name I. Balthica (Pallas), and in this he may be right, 

 but not being able to consult Pallas' work, I have preferred to use the 

 earliest name that I could certainly connect with the species, rather 

 than to introduce further confusion by adopting a name of the applica- 

 bility of which I could not satisfy myself. M. Sars also regarded J. 

 pelagica Leach as synonymous with I. tricuspidata, and says it is found 

 as far north as Tromsoe and southward to the Mediterranean, from which 

 statements I conclude that he intended the present species. 



This species is found along the whole coast of New England ! and 

 extends southward along the coast of New Jersey at least as far as 

 Great Egg Harbor ! and northward to Nova Scotia ! and the Gulf of St. 

 Lawrence, where it has been collected by Mr. J. F. Whiteaves. From 

 Cape Cod southward it is abundant, but toward the north it is, mostly 

 replaced by I. phosphorea. It is commonly found among sea- weed along 

 the rocky shores of bays and sounds or among the rocks, where its vari- 

 ety of colors affords it protection. It is also found far from land, 

 attached to floating sea-weed, and was thus taken by Professor S. I. 

 Smith and the writer on George's Banks !, September 14 and 15, 1872, 

 at about 41 N. lat., 65 W. Ion. One of these specimens was quite large, 

 measuring 38 mm in length, but most of them were of moderate size or 

 small. Young individuals are often taken at the surface. According to 

 European authors it is common on the shores of Great Britain and 

 Ireland (B. & W.) ; on all the shores of the North Sea (Metzger et al.); 

 (I. pelagica) as far north as Tromsoe (M. Sars) ; in the Baltic, the Medi- 

 terranean, the Adriatic (Heller, Stalio, et al.) 7 the Black (Czerniavski 

 et al.) and the Caspian (" Eichwald ") Seas, and, as with us, is of variable 

 color and varies also somewhat in the shape of the termination of the 

 pleon, which is, however, more or less three-toothed. 



Specimens examined. 



