NO. 1350. NATURAL HISTORY OF THE ISOPODA— RICHARDSON. 



45 



Fig. 21. — Young female of Phryxus, spe- 

 cies.? a, DORSAL view; b, VENTRAL VIEW. 

 XlO. 



Young female of Phryxus spJ — Body asymmetrical. Segm(>nts of 

 thorax detined only on the one side; other side g-roatly swollen. All 

 the legs of both sides present. 



Segments of abdomen distinct. 

 Terminal segment entire and pro- 

 duced in a long narrow process. Four 

 pairs of double-branched pleopoda 

 present. The outer lamella^ have the 

 proximal portion greatly dilated, be- 

 ing constricted about the middle on 

 one side and terminating in a narrow 

 elongated process; the inner lamellte 

 are small, tapering processes directed 

 toward the median line of the body. 



The marsupium consists of four pairs of plates, four of these being 

 large and conspicuous, the other four small and partly concealed by 

 one of the larger plates. 



Male. — Head large, broadly rounded in front; eyes 

 very small, and situated at extreme post-lateral angula- 

 tions; antennpe long. Segments of thoi'ax distinct; those 

 of the abdomen fused into one segment, whose extremity 

 is broadly rounded. 



Only one specimen, unattached, was obtained by the 

 U. S. Fish Commission steamer Alhatross at Omai Zaki 

 Light, at a depth of 36 to 48 fathoms. 



The young female described differs from the young 

 female of I*hri/xus ahdominalls (Kv0yQY)" in the shape 

 of the terminal segment of the body, in the shape of the 

 outer lamella^ of the pleopoda, and in having the inner 

 branches of the pleopoda directed toward the median line. 



The male differs from the male of P. ahdommalk in the larger 

 head, longer antenm^, and differently .shaped abdomen. 



ARGEIA PUGETTENSIS Dana. 



Argeia pugettensis Daxa, U. S. Expl. Exp. C'ru^t., II, ;). 804, pi. liii, fig. 7. — 

 Stimpson, Bost. Journ. Nat. Hist., VI, 1857, p. 71. — Rich.vrdson, Proc. U.S. 

 Nat. Museum, XXI, 1899, p. 868. 



LocalHy. — Tsuragi Saki Light, at a depth of 2.')".» and 110 fathoms; 

 Yokkaichi Light, at a depth of 13 and 16 fathoms; and Oboro Saki, 

 Japan, at a depth of 14 and IS fathoms. All parasitic on Cmiujon 

 ///'ophitj uihs i^timpson^ except those from the locality tir.st named, which 

 are parasitic on Crangon sp. 



Another specimen was collected at Mogi, Japan, by Dr. F. C. Dale 

 (l\ S. S. l*((Ios), which was parasitic also on Crangon j)r(>pi nquux. 



Fig. 2'J.— Male 

 OF Phryxus, 



SPECIES.? X 61. 



«Sars, Crustacea of Norway, II, 1899, pp. 214-217, pis. xo-xci. 



