anterior seta reaching beyond margin. Proximal part 

 of Ri with 3 proximal and 3 distal setae; Ri terminal 

 segment with 7 setae. 



Mxp Bl anterior surface with midlength cluster of 

 many thin spinules and distal series of short thin 

 setules; distal knob with 3 setae and short truncate 

 process. B2 proximal anterior surface with short 

 longitudinal row of short spinules of decreasing size 

 distally. Ri2-5 with nude inner and terminal setae. 

 Ri4-5 outer setae moderately long, with long plumes 

 on each side. 



PI (Figs. 176, 177) B2 and Rel outer distal edge 

 with few small teeth. Main body of Re2 outer spine 

 not reaching beyond two-thirds length of Re3; some 

 spines with a threadlike terminal part. Re3 outer 

 spine relatively wide. Ri outer lobe large, rhomboi- 

 dal. 



P2 (Fig. 178) Rel outer spine about two-thirds size 

 of Re3 outer spines. Re3 spiniform distal edge nearly 

 equaling size of outer distal spine. 



P3 (Fig. 179) B2 outer distal edge with 2-3 sharp 

 teeth. Rel outer spine smaller than R€2-3 outer 

 spines. Re3 spiniform distal edge as large as outer dis- 

 tal spine. 



P4 (Fig. 180) Bl posterior surface with inner 

 transverse row of very thin setules. B2 distal outer 

 edge with dull tooth. Re outer spines relatively small; 

 Rel outer spine smallest. Re3 outer spines not serrate. 

 Re3 spiniform distal edge as large as outer distal 

 spine. 



Re terminal seta with following number of teeth: P2 

 (52-65); P3 (56-67); P4 (ca. 61). 



Male.— Length 2.50 mm (Figs. 172, 173). Prosome 

 in dorsal view robust ovoid; anterior irregular, with 

 slight forward protrusion. In lateral view with 

 irregular, fairly abrupt forward slope. Prosome length 

 34 times urosome. Caudal rami length IV2 times 

 width. 



Al exceeding caudal rami by 2 segments. Vni- 

 2s, le; XI-ls, le; left segments 17-25 missing; 

 remainder as Table 4. 



Mn blade (Fig. 174) relatively complex; 5 strong 

 ventral teeth, 3 dorsal setiform processes. 



Mxl gnathobase reduced to 2-3 short, narrow teeth; 

 cluster of spinules on distal anterior surface. 



Mxp Bl distal lobe with 3 unequal setae. B2 with 2 

 small followed by 1 large midlength setae. Ri4-5 outer 

 setae reduced or absent. 



PI Re2 outer spine length as on female; Re3 outer 

 spine narrower than on female. 



P2 Rel outer spine as on female. 



P5 (Fig. 175) reaching middle of urosome segment 

 3. Left Bl reaching just beyond right Bl; left B2 

 reaching one-third length of right Rel. Left leg longer 

 than right by more than length of Re3. Left Re longer 

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

 segments: left 1, 2, 3; right 1 = 2, 3. Right Re3 small. 

 Each Rel with flat seta on outer distal edge, left 2 



times length of right. Rel-2 nearly fused left and 

 right. Inner edge of left and right Re2-3 with long 

 hairs, those of left Re3 in tufts. Each Re with short 

 bladelike terminal process. 



Remarks 



Farran (1908) reported only one female in the 

 original description; however, at least one other 

 specimen was taken in that survey and labeled 

 Mimocalanus nudus by Farran; this second specimen 

 was examined during the present study (sample 4, 

 Table 3). Farran separated M. nudus from M. 

 cultrifer essentially by size, but failed to note es- 

 pecially the differences in armature of the swimming 

 legs. Farran and Vervoort (1951b) illustrated P2 Ri2 

 with 1 outer seta. 



Brodsky (1950) first reported the distinctive 

 sclerotization on Ce and used this characteristic to 

 define a North Pacific species, M. distinctocephalus. 

 In the present study, this sclerotization was found to 

 be more or less developed on all Mimocalanus species. 

 Brodsky referred to this feature as a "band of 

 pigment"; however, it appeared in the present study 

 not to be pigmented. Brodsky (fig. 56, Nl) illustrated 

 PI Ri with 3 inner setae; this is considered in the pres- 

 ent study as an error, or an abnormality. Brodsky's 

 (fig. 56, N2) illustration of P2 Ri2 shows 1 outer seta. 

 No differences were found between North Pacific "M. 

 distinctocephalus" and Farran's M. nudus, and the 

 two forms are considered conspecific. 



Distribution 



Pacific Ocean 

 North: Brodsky (1950, 1957), 200-4,000 m. — Mi- 



noda (1971), 170-2,000 m. 

 Northeast: von Vaupel-Klein (1970), 0-1,200 



m. —Present study, 700-1,500 m. 

 Northwest: Brodsky (1950, 1952a, 1955, 1957), 



0-8,500 m. 

 Indian Ocean 



West: Grice and Hulsemann (1967), 1,000-2,000 



m. 

 Atlantic Ocean 

 Northeast: Farran (1908), 1,440 m. —Present 



study, 720-900 m. 

 East: Roe (1972a, b), 700-960 m. 

 Caribbean Sea: Park (1970), 980-2,800 m. 



3. Mimocalanus major Sars, 1920 



Mimocalanus major Sars, 1920, p. 4. — Sars, 1924, 

 1925, p. 35-36, pi. 10, fig. 1-16. 



Type Specimen: Holotype, female (4.20 mm), on slide, 



OSLO. 



Type Locality: Central North Atlantic, 0-3,000 m. 



72 



