urosome. Caudal rami length 1 ' 2 times width, 

 symmetrical. Caudal setae incomplete on specimens 

 examined; short stiff hair on outer margin of rami 

 may be remnant of sixth seta. 



Al reaching about end of prosome, left segment 20 

 merging with segment 21, typical of right-handed 

 males. IV-2s, 2e; VIII-2s, 2e; XV-ls, le; XIX-ls, 

 le; right XX-le; left XX-0; remainder as Table 4. 



Mn blade (Fig. 95) reduced; 7-8 short, subequal 

 teeth; short dorsal seta. 



Mxp (Fig. 96) Bl-2 without spine-combs, setae of 

 reduced size; longitudinal row of stiff hairs on B2. 

 Outer setae nude, reduced; no spinules on inner edge 

 of Ri5; large inner setae of last segments not inflated. 



Pi as on female, except Re outer spines shorter and 

 wider; spinules not seen on Re 1-2 distal anterior sur- 

 face; 4-5 spines on Re3 posterior surface. 



P2-P3 Bl with longer, thinner, and more numerous 

 spines than on female; B2, Rel, and Ril as on female. 

 P2 Ri2 proximal row of spines of decreasing length 

 from outer to inner edge, distal row of 5-6 large spines. 

 Re2-3 lacking on specimens examined. 



P4 Bl nude inner surface and margin; few short 

 setules on outer proximal surface, and minute 

 spinules on outer distal anterior surface. Rel and Ril 

 as on female. 



P5 (Fig. 97) biramus, right-handed: reaching mid- 

 dle of urosome segment 2. Right Bl reaching one-third 

 length of left B2; right B2 reaching middle of left Rel. 

 Right and left legs about equal; left Re, including ter- 

 minal blade, slightly longer than right; left Ri longer 

 than right. Order of length, longest to shortest, of Re 

 segments: left 3, 1 = 2; right 1 = 2, 3. Left Ri reaching 

 two-thirds length of Re long terminal seta. Right Ri 

 reaching middle of right Re3. Each Rel with short, 

 flat seta on distal outer edge. Inner edge of right Re2 

 with long hairs. Each Re with 1 small and 1 moderate 

 bladelike terminal setae. 



Remarks 



Brodsky (1950) did not describe Mxp nor P2 Ri; the 

 present specimens agree with Brodsky's description of 

 S. similis except for the symmetry of caudal rami and 

 the posterior surface spines on PI Re3. 



Brodsky (1955) briefly redescribed the male S. 

 similis as S. similis var. profundalis; the female which 

 he included in this variety is considered in the present 

 study as S. brevicaudatus. 



Distribution 



The only published records of S. similis are by 

 Brodsky, and the distribution of this species is sum- 

 marized below: 



Pacific Ocean 



Northwest: Brodsky (1950; 1952a, b; 1955, 



1957), 0-8,500 m. 

 Central: Present study, 0-1,000 m. 



Brodsky (1957) also indicated that S. similis was 

 found in "abyssal and lower bathypelagic" layers in 

 the Bering Sea. 



(22. Spinocalanus dorsispinosus 

 Brodsky, 1950) 



See Spinocalanus horridus Wolfenden, 1911. 



(23. Spinocalanus sp.? Brodsky, 1950) 



{Spinocalanus abyssalis. — Tanaka, 1937) 



Female, see Spinocalanus horridus Wolfenden, 

 1911. Male, see S. brevicaudatus Brodsky, 1950. 



(24. Spinocalanus longispinus 

 Brodsky, 1950) 



See Spinocalanus horridus Wolfenden, 1911. 



25. Spinocalanus elongatus Brodsky, 1950 



(Figures 98-113, 155) 



Spinocalanus elongatus Brodsky, 1950 (part), p. 132- 

 133, fig. 52; female and "male variant" but not 

 "male." — Vidal, 1971, p. 18, 23, fig. 46-47, 50-51, 

 56-57. 



Type SPECIMEN: Unknown. 

 Type Locality: Central Arctic Ocean, 50 m. 

 Material Studied: 8 females (1.50-1.80 mm, mean 

 = 1.65 mm), sample Al (Table 1); 6 females (1.58-1.80 

 mm, mean = 1.64 mm), sample A2; 20 females (1.50- 

 1.80 mm, mean = 1.61 mm), 1 female stage V (1.37 

 mm), and 2 males (1.45, 1.55 mm), sample A4; 9 

 females (1.58-1.70 mm, mean = 1.64 mm), 1 female 

 stage V (1.54 mm), and 1 male (1.62 mm), sample A5; 



1 female stage V (1.70 mm), 11 female stage IV and 2 

 male stage IV (1.15-1.23 mm), 12 stage III (0.8-1.05 

 mm), and 2 male stage V (1.48, 1.53 mm), sample A6; 



2 males (1.60 mm), sample A20; 1 male (1.68 mm), 

 sample A21; 1 male (1.56 mm), sample A23; 7 males 

 (1.60-1.76 mm, mean = 1.66 mm), sample A24; 2 

 males (1.60, 1.64 mm), sample A27; 1 female (1.68 

 mm), sample A31; 2 males (1.70, 1.72 mm), sample 

 A33; 12 females (1.50-1.72 mm, mean = 1.61 mm) and 

 1 male (1.68 mm), sample A48. 



Description 



Pi Ri with 2 inner setae; P2 Ri2 with no outer seta. 



Female.— Length 1.50-1.80 mm (Figs. 98, 99). 

 Prosome in dorsal view ovoid, head somewhat trun- 



46 



