A REVIEW OF THE MYSIDACEA 31 



terolateral spines of the carapace project backward. The specimens 

 are arranged in order of length commencing with the largest. 



The table brings out quite clearly the fact that the rostral and 

 posterolateral spines of the carapace gradually shorten, in relation 

 to the total length, as the animal increases in size. I have nothing 

 to add to the elaborate discussion given by Ortmann of age changes in 

 this species, but I present the above table as evidence in support of 

 his conclusions. 



GNATHOPHAUSIA ZOEA var. SCAPULARIS Ortmann 



Gnathophausia scapularis Ortmann, 1906, p. 50, pi. 2, figs. 3a-c. 

 Gnathophausia zoea var. scapularis Tattersall, 1939a, p. 226, figs. 1, 2. 



Occurrence. — California coast: Albatross station 2992*, identi- 

 fied by Ortmann, types. 



Distribution. — Off Baja California and the Indian Ocean. 



GNATHOPHAUSIA ELEGANS G. O. Sars 



Gnathophausia elegans G. O. Sars, 1884, p. 7 ; 1885, p. 42, pi. 6, figs. 1-5.— Ort- 

 mann, 1906, p. 51.— Hansen, 1910, p. 18.— Tattersall, 1939a, p. 228. 



Occurrence. — Japan: Albatross stations 4906, 1 female, 34 mm.; 

 5060, 1 female, 34 mm.; 3697*, identified by Ortmann (1906). Phil- 

 ippine Islands : Albatross stations 5115, 1 female, 36 mm. ; 5287, 1 im- 

 mature, 16 mm. ; 5359, 1 male, 52 mm. ; 5449, 1 female, 38 mm. ; 5463, 1 

 male, 43 mm. ; 5466, 1 male, 46 mm. ; 5468, 1 male, 42 mm. ; 5471, 5 

 damaged specimens; 5619, 1 male, 45 mm., 1 female, 34 mm.; 5631, 1 

 female, 38 mm. 



Distribution. — This species is not known from the waters off either 

 the east or west coasts of America. It has a distribution comparable 

 with that of G. longispina, confined to the western part of the Pacific 

 Ocean and the Indian Ocean. Like G. longispina, too, it is found in 

 the more moderately deep rather than the very deep waters of the 

 area of its distribution. The present material comes from the waters 

 to the south of Japan and the waters around the Philippine Islands. 

 The previous records are from south of the Fiji Islands (Sars), off 

 Japan (Ortmann), the waters of the East Indian Archipelago (Han- 

 sen), and the Indian Ocean (Tattersall). 



Remarks. — In table 6 measurements are given similar to those 

 for G. gigas and G. zoea to illustrate the changes in the relative 

 lengths of the rostrum and posterolateral spines of the carapace 

 which accompany growth. In all cases the total length given is meas- 

 ured from the eye to the end of the telson. 



This is one of the rarest species of the genus and the present col- 

 lection is twice as large as the sum of all previous records. It is, 

 therefore, the first material on which any change of proportion with 



