86 RATHBUN 



SPIRONTOCARIS GAIMARDII BELCHERI (Bell). 



Plate in, figs. 3, aa. 



Hippolyte belcheri BELL, in Appendix to Belcher's Last of the Arctic Voyages 



in Search of Sir John Franklin, II, 402, pi. XXXIV, fig. I, 1855. 

 ? Hippolyte layi LOCKINGTON, Bull. Essex Inst., X, 161, 1878 (not H. layi 



Owen). 

 Hippolyte gaimardii MURDOCH, Kept. Exped. Point Barrow, p. 140, 1885 



(part). 

 Spirontocaris gibbet RATHBUN, The Fur Seals and Fur-Seal Islands of the 



North Pacific Ocean, Pt. Ill, 556, 1899. 

 Hippolyte gibba BIRULA, Ann. Mus. Zool. Acad. Imper. Sci. St. Petersbourg, 



VII, 428 [n], text fig. i, 1899 [1900] (probably not H. gibba 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 9 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. 



