INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. bb\) 



In the feuiale the hands of the first and second pairs of legs are 

 smaller and slenderer, and the propodi somewhat oval and nearly alike 

 in both pairs; otherwise the females do not differ from the males, except 

 that the rami of the posterior caudal stylets are, perhaps, a very little 

 shorter and broader in proportion. 



Length, 10-12""". 



Vineyard Sound, in vast numbers at the surface of the water, usually 

 among floating sea- weeds and eel-grass. Also from stomach of mackerel,. 

 May 20. 



Gammarus marinus Leach, (p. 180.) 



Trans. Linnean Soc, London, vol. xi, p. 359, 1815; Bate, Catalogue Ampliip. 

 Crust., Brit. Mus., p. 215, PI. 38, fig. 4 ; Bate and Westwood, Brit. Sessile-eyed- 

 Crust., vol. i, p. 370, wood-cut. 



A species which I cannot distinguish, by the published figures and 

 descriptions, from this common species of Europe, was not uucommon ? 

 associated with Amphithoe maculata, under stones at the Wepecket 

 Islands, Gull Island, Cuttyhunk Island, and at other places on Vine- 

 yard Sound and Buzzard's Bay. It has also been found at ^atch Hill, 

 Rhode Island, and at New Haven, Connecticut, by Professor Verrill. 

 It is at once distinguished from all the other species of our coast by its- 

 slender form, slender antenna 1 , by having the sides of the second and 

 third segments of the abdomen narrow and not produced or acute at the 

 postero-inferior angle, and by having the outer rami of the posterior 

 caudal stylets four or five times as long as the inner. 



Gammarus mucronatus Say. (p. 479.) 



Loc. cit., p, 376, 1818; De Kay, op. cit., p. 37. Gammaracanthus mucronatus Bate,. 

 op. cit., p. 203. 



Readily distinguished from the other species of the coast by having 

 the x>osterior margin of each of the anterior segments of the abdomen 

 produced into a slender, spiniform, dorsal tooth. In life, it is translu- 

 cent, tinged with green, or yellowish green, minutely specked with brown 

 or black ; these black or brown markings and the green color being fre- 

 quently so arranged as to give the antennae and legs a banded appear- 

 ance. Our species cannot be referred to Bate's genus Gammaracanthus r 

 for the dorsal margin is not distinctly carinated, and the third, fourth, 

 and fifth segments of the abdomen are furnished with fascicles of spines. 



Usually in brackish water, North Carolina to Cape Cod, and, accord- 

 ing to Say, from Florida also. 



Mcera LEVIS Smith, sp. nov. (p. 315.) 



Eyes nearly round; black in alcoholic specimens. Autennula two- 

 thirds as long as the/body ; first and second segments of the peduncle 

 equal in length, third about two-thirds as long as the second ; fiagellnm 

 about as long as the peduncle. Antenna about as long as the peduncle 

 of the antennula ; ultimate and penultimate segments equal in length, 

 antepenultimate very short ; fiagellnm much shorterthan the peduncle. 

 Legs of the first pair small ; carpus as broad as the propodus, but little 



