Mxp Bl with row of thin setules on midanterior sur- 

 face, and 4 clusters of thin spinules on outer posterior 

 surface; distal lobe anterior surface covered with 

 setules; 1 relatively long and 1 small distal setae, and 

 1 long truncate distal process. B2 with longitudinal 

 row of stiff hairs; 2 midlength setae, followed by more 

 distal seta and 2 distal setae. Ri segments rhom- 

 boidal; inner subterminal setae short (some probably 

 missing from specimens examined), but terminal seta 

 thick, not expanded, probably very long (broken). 

 Ri4-5 outer setae relatively thick and long; each side 

 with long plumes. 



PI B2 with small outer seta and long inner anterior 

 seta, as in other Spinocalanidae. B2 inner edge 

 without hairs; Rel nude. Ri outer lobe reduced to 

 small lamella. 



P2-P3 Bl inner edge with hairs and 1 seta; outer 

 anterior surface with few setules. Specimens exam- 

 ined lacked P2-P4 Re2-3. 



Male. — Unknown. 



Remarks 



Mimocalanus ovalis has some characteristics of 

 Spinocalanus species: relative lengths of Al segments 

 1-2 and complete fusion of segments 8-9, and arma- 

 ment and spacing of setae on Mxp B2. However, the 

 lack of outer distal spine on PI Rel, lack of surface 

 spines on swimming legs, number of setae on Ri of 

 swimming legs, 3 inner setae on Mn B2, form of Mxp 

 Ri4-5 outer setae, and prolonged Th5 would indicate 

 placement with Mimocalanus species. Specimens 

 with complete Re of swimming legs should be exam- 

 ined. 



Grice and Hulsemann (1967) briefly described 

 females of a new species Spinocalanus ventriosus. Ex- 

 cept for a slight knoblike protrusion at the tip of Th5, 

 their description is consistent with that of 

 Mimocalanus ovalis. The knobiike protrusion could 

 be an artifact, caused by a contraction of the body 

 walls at that point, as it appeared to be in the 

 holotype examined in the present study. The holotype 

 was lacking Al distal segments, P1-P4 Re2-3, P2 Ri2, 

 and P3-P4 Ri2-3. PI Rel, PI Ri, P2-P3 Bl, Al 

 segments 1-2 and 8-9, and Mxp B2 as in M. ovalis. 

 There was no indication of an outer spine on PI Rel; 

 usually a socket, or at least a torn thread, can be seen 

 if the spine is detached. The holotype lacked the 

 swimming leg segments that would have surface 

 spines in Spinocalanus, so that placement of S. ven- 

 triosus with Mimocalanus ovalis may still be 

 questionable. 



Distribution 



Indian Ocean 



West: Grice and Hulsemann (1967), 

 4,000 m. 



1,000- 



Atlantic Ocean 



Northeast: Grice and Hulsemann (1965), 1,900- 

 5,000 m. 



(7. Mimocalanus species Grice and 

 Hulsemann, 1967) 



See Mimocalanus crassus Park, 1970. 



8. Mimocalanus crassus Park, 1970 



(FiKxires 161, 181-191) 



Mimocalanus species Grice and Hulsemann, 1967, 



p. 21, fig. 19-25. 

 Mimocalanus crassus Park, 1970, p. 478-481, fig. 1-12. 



Type Specimen: Holotype, female (0.95 mm), USNM 

 123771. 



Type Locality: Caribbean Sea, 487-2,800 m. 

 Material Studied: Holotype, female (0.95 mm), 

 sample 55 (Table 3); 1 female (1.08 mm), sample A5 

 (Table 1); 1 female (1.0 mm), sample A6; 1 female 

 (1.20 mm), sample A23; 2 males (1.27, 1.36 mm), sam- 

 ple A29; 3 females (1.16, 1.20, 1.24 mm) and 1 male 

 (1.24 mm), sample A31; 3 males (1.08 mm), sample 

 A32; 1 female (1.20 mm), sample A33; 1 female (1.20 

 mm), sample A36; 2 females (1.16, 1.24 mm), sample 

 A45; 3 females (1.20, 1.26, 1.27 mm) and 1 male (1.22 

 mm), sample A48; 23 females (1.08-1.25 mm, mean = 

 1.12 mm) and 1 male (1.04 mm), sample A51. 



Description 



Right PI Ri with 2 inner setae; left PI Ri with 1 

 inner seta, distal. P2 Ri2 with no outer seta. P3-P4 Ri3 

 with no outer seta. P2-P4 Bl without inner seta. 



Female.— Length 0.95-1.27 mm (Figs. 181, 182). 

 Prosome in dorsal view robust ovoid; head rounded. In 

 lateral view with abrupt forward slope. Th4 and Th5 

 separate. Prosome length 4 '/a times urosome. Genital 

 segment length three-fourths times width, protruding 

 ventrally one-fourth depth of rest of urosome. Caudal 

 rami length slightly greater than width. 



Mimocalanus crassus 



Figure 181. — Female, habitus, dorsal view; scale B. 



Figure 182. — Female, habitus, lateral view; scale B. 



Figure 183.— Female, Mn blade; scale D. 



Figure 184.— Female, PI; scale D. 



Figure 185.— Female. P2; scale D. 



Figure 186.— Female, P3; scale D. 



Figure 187.— Female, P4; scale D. 



Figure 188.— Male, habitus, dorsal view; scale B. 



Figure 189.— Male, habitus, lateral view; scale B. 



Figure 190.— Male, Mn blade; scale D. 



Figure 191.— Male, P5; scale D. 



74 



