A REVIEW OF THE MYSIDACEA 81 



the male with the exopod elongate, its endopod and the other pairs of 

 pleopods either well developed or reduced in varying degree ; first ab- 

 dominal somite of the female with a pair of lateral lamellae, which 

 take part in the formation of the brood pouch ; exopod of the uropod 

 undivided, its outer margin with one, two, or several spines, but with- 

 out setae between the spines and the base ; telson with a distinct apical 

 cleft. 



Remarks. — Five genera are included in this subfamily — Archaeomy- 

 sis, Gastrosaceus, Anchialina, Par anchialina, and Pseudanchialina. 

 The first three occur in the National Museum collection. 



Genus ARCHAEOMYSIS Czerniavsky 



Archaeomysis Czeeniavskt lS82a, pp. 62, 71, 73. — Hansen, 1910, p. 50. — Tatter- 



saix, 1932a, p. 303. 

 Callomysis Holmes, 1894, p. 582. 



This interesting genus was established in 1882 by Czerniavsky for 

 a mysid found in the stomach of a gadoid fish caught at Bering 

 Island, Alaska, by Grebnitzky in 1880. Its outstanding characteristic 

 is that the pleopods of the female, while feebly developed and non- 

 natatory, are all biramous. In 1894 Holmes founded the genus Cal- 

 lomysis, describing the pleopods of the female as rudimentary but 

 biramous. In 1910 Hansen, without having seen specimens, suggested 

 that the genera Archaeomysis and Callomysis were identical, and, in 

 1932 I was able to confirm Hansen's suggestion from the examination 

 of specimens that I referred to Callomysis maculata Holmes. Czerni- 

 avsky's species Archaeomysis grebnitzkii has not been recorded since 

 its description, but specimens in the collection of the United States 

 National Museum, which I refer with some confidence to this species, 

 have enabled me to redescribe the species and to confirm Czerniavsky's 

 description. The genus is very closely allied to Gastrosaceus and 

 to be distinguished only by the biramous pleopods of the female. 



ARCHAEOMYSIS GREBNITZKII Czerniavsky 

 Figures 21, 22 



Archaeomysis grebnitzkii Czerniavsky, lS82a, p. 73 ; 1S87, p. 1, pi. 30, figs. 17-24 ; 

 pi. 32, figs. 19-20.— Zimmee, 1904, p. 428, figs. 26, 27. 



Description. — Carapace without reflected lobes or fringe or filaments 

 on the posterior margin ; produced in front into a short, broadly tri- 

 angular rostral plate with a bluntly rounded apex, the whole rostral 

 plate shorter than the eyestalk, apex slightly depressed. 



Eye somewhat pyriform in shape; whole eye including the stalk 

 rather less than twice as long as broad, cornea occupying about one- 

 half the entire eye, pigment black. 



