86 RATHBUN 
SPIRONTOCARIS GAIMARDII BELCHERI (Bell). 
Plate 111, figs. 3, 3a. 
Hippolyte belcheri BELL, in Appendix to Belcher’s Last of the Arctic Voyages 
in Search of Sir John Franklin, 11, 402, pl. XXXIV, fig. 1, 1855. 
2? Hippolyte dayi LOCKINGTON, Bull. Essex Inst., X, 161, 1878 (not HZ. dayz 
Owen). 
Hippolyte gaimardit MURDOCH, Rept. Exped. Point Barrow, p. 140, 1885 
ee gibba RATHBUN, The Fur Seals and Fur-Seal Islands of the 
North Pacific Ocean, Pt. III, 556, 1899. 
Hippolyte gibba BIRULA, Ann. Mus. Zool. Acad. Impér. Sci. St. Pétersbourg, 
VII, 428 [11], text fig. 1, 1899 [1900] (probably not H. gzbba Kroyer). 
Female.—Robust. Rostrum longer than the carapace, nearly hori- 
zontal posteriorly, anterior half ascending, armed above with 8 to 12 
teeth (including 2 to 4 on the carapace), below with 3 to 5 teeth; ros- 
trum tapering gradually to an acuminate tip, which exceeds the antennal 
scale. A strong antennal and a well-developed pterygostomian spine. 
Eyes rather large, pyriform. Scale at base of antennules reaches one 
third the length of the second segment of the peduncle. Peduncle half 
as long as antennal scale; second segment twice as long as third; 
thickened portion of outer flagellum not reaching the tip of antennal 
scale, but sometimes as far as the acicular spine. This scale is shorter 
than the carapace; blade arcuate at extremity and exceeding the spine. 
The peduncle reaches about two fifths the length of the scale; the 
maxilliped to the distal third of the same; the first pair of feet to 
the end of the antennal peduncle; the second pair to a little beyond 
the antennal scale; the fifth pair overreaches the maxillipeds. 
The fourth and fifth segments of the abdomen are each armed with 
a postero-lateral spine. The third segment is laterally compressed in its 
posterior part, which has an angular median lobe, seen in profile, a little 
in front of the posterior margin; on very large females this lobe becomes 
hook-shaped (as on one 80 mm. long). The sixth segment is about two 
and a half times as long as high, and shorter than the seventh, which is 
armed with 5 to 8 spines on each side. The outer uropods are longer 
than, the inner ones shorter than, the telson. 
Male.—More slender than the female. Rostrum more nearly straight 
and horizontal, 8 or g teeth above. Thickened portion of outer anten- 
nular flagellum exceeding acicle. Lobe on third segment of abdomen 
more prominent and hooked. 
Young.—In those one inch long and smaller the abdomen shows no 
median lobe on third segment, though it is slightly compressed. The 
antennular scale does not reach beyond the first segment of the peduncle. 
