A REVIEW OF THE MYSIDACEA 197 



off Newport, R. I., 13 fathoms, sand bottom, August 24, 1880, 2 speci- 

 mens; 1058, Chesapeake Bay, south end of Barren Island, 3 to 25 

 fathoms, brown mud bottom, February 28, 1882, 1 male; 1059, Chesa- 

 peake Bay, south end of Barren Island, 2% to 25 fathoms, brown mud 

 bottom, February 28, 1882, 1 male; 1077, Sandy Point Lighthouse, 11 

 to 12 fathoms, mud bottom, March 13, 1882, 1 male; 1239*, Block 

 Island South, Mass., No Man's Land, August 30, 1887, 16 fathoms, 

 identified by S. I. Smith. Bache station 10157, off Cape Henry, Va., 

 latitude 36°46' N., longitude 75°38' W., surface, January 20, 1914, 

 many specimens. Casco Bay and off Montauk Point*, identified by 

 S. I. Smith. 



Distribution. — This species is confined to the east coast of North 

 America, where it ranges from the Gulf of St. Lawrence to the coast 

 of Virginia in shallow water 



Remarks. — Neomysis americana may be distinguished by the follow- 

 ing characters: (1) The carapace is produced into a broadly rounded 

 rostral plate. (2) The eye, including the stalk, is l 1 ^ times as long as 

 broad at the widest point, stalk narrower than the cornea, latter oc- 

 cupying at least half of the whole eye. (3) The antennal scale (fig. 

 77, a) is ten times as long as broad. (4) The sixth joint (fig. 77, b) of 

 the endopod of the third to the eighth thoracic limbs divided into 8 to 9 

 joints. (5) The telson (fig. 77, e) is triangular in shape, 2!/2 times as 

 long as broad at the base, with a narrowly truncate apex armed with 

 two pairs of spines, the outer pair three times as long as the inner pair ; 

 lateral margins armed with about 40 spines which, on the distal two- 

 thirds of the margins at least, are arranged in groups with one to three 

 smaller spines between the larger spines. (6) The proximal joint of the 

 exopod of the fourth pleopod of the male is seven times (fig. 77, c) as 

 long as the distal ; latter joint about half as long as the terminal pair of 

 setae. 



This species has never been adequately figured. W. L. Schmitt 

 (1919) gave a figure of the distal part of the telson, but no other 

 author has illustrated the species in anything but a general way. I 

 therefore here give figures to illustrate the salient features of the 

 species. Zimmer (1904 and 1909) was inclined to regard this species 

 as merely a local variety of Neomysis integer (Leach), but the two 

 species are in reality very distinct in the form of the telson. In N. 

 integer there are only about 22 spines on the lateral margins of the 

 telson, more or less evenly spaced and not in any way arranged in series 

 of smaller and larger spines. In N. americana there are about 40 spines 

 on the lateral margins, and at least distally these are grouped with one 

 to three smaller spines between the larger ones. The proportions of 

 the joints of the exopod of the fourth pleopod of the male also differ 

 markedly in the two species. 



