A REVIEW OF THE MYSIDACEA 235 



Genus HETEROMYSIS S. I. Smith 



Heteromysis S. I. Smith, 1873, p. 553. 

 Chiromysis G. O. Saks, 1877, p. 56. 

 Gnathomysis Bonnier and Perez, 1902, p. 117. 



This genus is represented on both the east and west coasts of Amer- 

 ica, on the east coast by H. formosa, H. bermudensis, and H. antillensis, 

 and on the west coast by H. odontops, with which I regard II. spinosa 

 as synonymous. The west coast species can be distinguished from 

 all the east coast forms by the extension of the spines arming the lateral 

 margins of the telson along the whole length of the margins, whereas 

 in the east coast species the spines occupy only the distal half of the 

 margins. The key will help to identify the species : 



KEY TO THE SPECIES OF HETEROMYSIS 



o *. Telson with spines along full extent of lateral margins ; 20 to 24 spines on 

 lateral margins of telson ; cleft of telson one-fourth to one-third length of 

 telson with spines along full extent of margins of cleft ; eye with a tuber- 

 cular process on inner corner of stalk odontops(p. 239) 



a \ Telson with spines along distal half of lateral margins only. 



b K Twelve to 16 spines on lateral margins of telson; cleft of telson one-third 

 length of telson with spines along full extent of its margins. 



formosa (p. 235) 



b*. Six spines on lateral margins of telson; cleft of telson one-third length of 

 telson with spines along proximal part of its margins only; distal part of 

 each margin being smooth and devoid of spines bermudensis (p. 237) 



I am unable to place H. antittensis in this key. Verrill's description 

 is entirely inadequate and does not record any of the fundamental 

 characters of the species. In all probability it is not specifically 

 separable from H. bermudensis. 



HETEROMYSIS FORMOSA S. I. Smith 



Figures 100, 101 



Heteromysis formosa S. I. Smith, 1873, p. 553; 1879, p. 101. — Benedict, 1885, 

 p. 175.— Paulmier, 1905, p. 129.— M. Rathbun, 1905, p. 28.— Fowleb, 1912, 

 p. 541.— Sumner, Osborn, and Cole, 1913, p. 663.— Pratt, 1916, p. 383 ; 1935, 

 p. 423.— Allee, 1923a, p. 180 ; 1923b, p. 227.— Fish, 1925, p. 152. 



Occurrence. — East coast of United States : Woods Hole, 1 imma- 

 ture female; Woods Hole region, 18 females, 9 males; Woods Hole, 

 surface, 8 p. m., October 2, 1882, 2 immature specimens; Vineyard 

 Sound, 1875, 84 breeding females, 60 adult males, 13 immature ; Vine- 

 yard Sound, December 28, 1877, V. N. Edwards collector, 4 females, 

 3 males ; Vineyard Sound, 1 breeding female ; Vineyard Sound, iden- 

 tified by S. I. Smith* ; Newport, R. I., 1880, shore to 30 fathoms, 2 imma- 



