A REVIEW OF THE MYSIDACEA 151 



rounded and convex and armed with about 30 to 34 short spines; 

 lateral margins terminating in a spine but otherwise unarmed. 



Inner uropod (fig. 55, 1) one and a third times as long as the telson, 

 inner margins armed with a row of spines from the statocyst to the 

 apex, the spines arranged in series of smaller spines between larger 

 ones in the proximal three-quarters of the row, distal three spines 

 large, widely separated, and without smaller ones between them. 

 Outer uropod twice as long as the telson. 



Length. — Adult specimens of both sexes 6 to 7 mm. 



Occurrence. — California: La Jolla, Scripps Institution, haul 87, 

 August 19, 1916, 12 specimens; haul 377, September 21, 1916, 3 speci- 

 mens; haul 432, October 3, 1916, 7 specimens; haul 586, October 17, 

 1916, 5 specimens; haul 1237, January 13, 1917, 4 specimens; haul 

 1789, May 10, 1917, 1 specimen: haul 1846, May 23, 1917, 1 specimen; 

 haul 1966, June 6, 1917, 6 specimens; haul 2301, June 29, 1917, 3 speci- 

 mens; haul 2308, August 23, 1917, 1 specimen. San Pedro* identified 

 by M. J. Rathbun. 



Distribution. — Known only from the coast of California, where 

 it appears to be an abundant planktonic species during the hours of 

 darkness. 



Remarks. — This species is most closely related to M. pacifica (Zim- 

 mer) , and in 1932 I suggested that the two species were synonymous in 

 spite of small differences to be noted between California specimens 

 and the description and figures given by Zimmer of M. pacifica. Coif- 

 mann (1937) considers the two species distinct and finds that the 

 differences I pointed out are constant in numerous examples of M. 

 pacifica she has examined. Under the latter species I give a sum- 

 mary of these differences. I have not seen any specimens of M. 

 pacifica. M. elongata is also closely related to M. munda and differs 

 mainly in the form of the telson. Both species have the same type 

 of maxilla, without exopod and inner setiferous expansion. 



METAMYSIDOPSIS PACIFICA (Zimmer) 



Diagnosis of this species may be found on page 245. 



Genus PROMYSIS Dana 



Promysis Dana, 1850, p. 130. 

 Uromysis Hansen, 1910, p. 71. 



PROMYSIS ORIENTALIS Dana 



Promysis orientalis Dana, 1852b, p. 651 ; 1855, pi. 43, fig. 4a-c. — Czerniavsky, 



1887, p. 40.— Tattersall, 1936b, p. 154, fig. 5. 

 Uromysis armata Hansen, 1910, p. 72, pi. 11, figs. 2a-n. — Zimmer, 1915b, p. 170. — 



Colosi, 1919, p. 9 ; 1920, p. 243. 



Occurrence. — Philippine Islands: Albatross stations 5596, 1 male, 

 1 female ; 5669, 10 males, 3 females. 



893476 — 51 11 



