428 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



extend forward in the natural position about to the tips of the antennse; 

 they have the basal segment subquadrate, the hand or propodus less 

 robust than the carpus, with a serrated digital process ; dactylus short. 



The second, or first free, thoracic segment is about two-thirds as long 

 as the third ; this in turn is about equal to the fourth and to the fifth seg- 

 ments; while the sixth and seventh segments are progressively some- 

 what shorter. The second pair of legs are scarcely more slender than the 

 following pairs, and the basal segments are not curved, around the base 

 of the first pair. 



The uropods (pi. XIII, fig. 91 c) are short, and biramous; each ramus 

 two-jointed. The outer ramus is more slender than the inner, half its 

 length, and bears a long bristle at the tip. 



Length 2.5 mm ; color white. 



The first specimen of this species was dredged along with L. limicola 

 in 48 fathoms, soft mud, Massachusetts Bay!, off Salem, in the summer 

 of 1877, and a second specimen apparently of the same species, though 

 differing somewhat in the antennulse. was collected on the shore at 

 Provincetowii ! during the summer of 1879. Unfortunately only a single 

 specimen was obtained in each case, but it is very distinct from the 

 other species of our coast. It does, however, closely approach Tanais 

 islandicus G. O. Sars,* but appears to differ in the first pair of legs, 

 which Sars describes as follows: "Pedes primi paris validi, manu sat 

 dilatata, carpo vix angustiore, digitis palma3 longitudinem requantibus 

 vix forcipatis." These legs are in our species distinctly chelate, and the 

 dactylus is much shorter than the propodus (see pi. XIII, fig. 91 b). He 

 further says : " Uropoda sat elongata, birarnosa, ramis, ambobus biar- 

 ticulatis, valde ina3qualibus, exteriore ne 3 tiam quidem interioris longitu- 

 dinus partein assequente." In our species the outer ramus of the uropod 

 is about one-half as long as the inner. 



GEOGRAPHICAL DISTRIBUTION. 



The whole number of species enumerated is forty-six, three more than 

 were included in my recent paper on New England Isopoda in the Pro- 

 ceedings of the United States National Museum. Their geographical 

 distribution, especially on our coast, is summarized in the lists below. 



The following eleven species have as yet been found only south of 

 Cape Cod : 



Scyphacella arenicola. 

 Actouiscus ellipticus. 

 Cepon distortus. 

 Bopyrus species. 

 Erichsonia filiforruis. 

 Erichsonia attenuata. 



Cirolana concharum. 

 Nerocila nmnda. 

 JEgathoa loliginea. 

 Livoneca ovalis. 

 Tanais vittatus. 



*Archiv for Mathematik og Naturvidenskab, Bind ii, p. 346 [246], 1877. 



