64 RATHBUN 
Ross (loc. cit.) probably represents the % of S. sina, but the shape of 
the rostrum is inaccurate; both upper and lower lamine should have 
more convex margins. 
Distribution.—Circumpolar. Arctic Alaska, Bering Strait, Bering Sea, 
Aleutian Islands, and Alaska Peninsula to Lituya Bay, 5-91 fathoms; 
Atlantic Ocean southward to Massachusetts Bay, 5-90 fathoms; 
northern Europe: 
Taken by the Albatross at the following stations: 
Off the Pribilof Islands, 41-62 fathoms, stations 3439, 3442, 3482, 3483, 
3485, 3505, 3540, 3544, 3554, 3560, 3561. 
Off Bristol Bay, 30 fathoms, station 3302. 
Off Cape Strogonof, 30 fathoms, station 3293. 
Off Kudobin Islands, 36 fathoms, station 3280. 
Off Akutan Island, 56-91 fathoms, stations 2841, 2842, 3548. 
Pumicestone Bay, Unalaska, 35 fathoms, station 3322. 
Northwest of Unimak Island, 81 fathoms, station 3257. 
South of Unimak Island, 42 fathoms, station 3217. 
Between Bird and Nagai Islands, Shumagins, 35 fathoms, station 2851. 
Collected by Dr. Dall at: 
Bering Strait, 12 fathoms. 
Bay of Islands, Adak, 9-16 fathoms. 
Nazan Bay, Atka, 10-16 fathoms. 
Captains Harbor, Unalaska, 9-80 fathoms. 
Port Levashef, Unalaska. 
Lituya Bay, 6-g fathoms. 
Off Point Hope, Arctic Alaska, 25 fathoms (U.S. R. S. Corwin). 
Lorenz Bay and Plover Bay (Richters). 
SPIRONTOCARIS ARCUATA Rathbun. 
Platevinm, sigsea. 
Spirontocaris spinus RATHBUN, The Fur Seals and Fur-Seal Islands of the 
North Pacific Ocean, Pt. III, 556, 1899 (part). 
Spirontocaris arcuata RATHBUN, Proc. U. S. Nat. Mus., xxiv, 893, 1902. 
On the Pacific coast, associated in part with S. spina, is a very closely 
allied species, easily mistaken for S. sfzza, but apparently distinct. In the 
peers adult g , the upper line of carapace and ros- 
Sa SS trum in profile forms a single curve, without 
\, the sinus shown in 5S. sfiza, the rostrum is on 
} a higher level than in that species, the rostral 
spines larger and more distinctly marked; the 
ieee apie of eo Ge), “Sx posterior lobe of the third abdominal segment 
ter shorter and broader; the sixth segment con- 
siderably shorter, being less than one and a half times as long as wide, 


