246 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



1961, table 5.— Zoppi, 1961, table 4.— Breuer, 1962, p. 167.— Cronin, Daiber, 

 and Hulbert, 1962, p. 87.— Bjornberg, 1963, pp. 27-28.— Reeve, 1964, 

 passim. 

 Scolecithrix ancorarum Oliveira, 1947, pp. 460-461, pi. 3, figs. 1-8. 



Female. — Length 0.73-0.93 mm. Prosome : urosome = 2.8-3.2. 

 Head moderately high, rostral filaments filiform. Prosome usually 

 with distinct dorsal hump in region of Mxl. Innermost caudal 

 setae only half as long as caudal ramus. Al nearly as long as body. 

 Thu-d lobe of Bl of Mxp with 2 setae. Bl of P3 and P4 with lateral 

 rows of spinules and surface spinules as shown in figure. Inner 

 terminal spine of P5 5-6 times as long as outer terminal spine, only 

 a little longer than distal segment. 



Male. — Length 0.76-0.78 mm. Prosome:urosome = 2.3-2.5. 

 Head not as flat as in female. Spinules on Bl of P3 and P4 reduced or 

 missing. P5 as in figure 3i. 



Distribution. — Worldwide, in tropical, temperate, and sometimes 

 Arctic seas, usually in coastal waters. 



Oliveira's (1947) Scolecithrix ancorarum is ob\dously a Paracalanus. 

 The size (1 mm.) and thin rostral filaments rule out P. crassirostris. 

 The short antennae and the presence of spinules on Bl of P4 place it 

 in P. parvus rather than P. aculeatus. 



Family Pseudocalanidae 



Small calanoids, head and PedSeg 1 (at least in female), PedSegs 

 4 and 5 fused. Innermost and outermost caudal setae very short, 4 

 subequal terminal setae. Al 24-segmented in female, with fewer 

 segments in male. Re of A2 longer than Ri. Mouthparts reduced 

 in male. Re of P1-P4 3-segmented, Ri of Pi 1-segmented, Ri of P2 

 2-segmented, Ri of P3-P4 3-segmented. Re3 of P2-P4 with 3 

 outer spines and 4 inner setae, terminal spine serrate. Female P5 

 very small or absent, uniramose, composed of 2-3 short segments; 

 right male P5 5-segmented, left P5 shorter. 



Genus Clausocalanus Giesbrecht 



Rostral filaments spiniform in female, atrophied in male. B2 of P2 

 and P3 very wide, distal margin dentate. Female P5 3-segmented, 

 without setae, distal segment bifurcate at tip. Male left P5 long, 

 5-segmented, right P5 minute, 1-3-segmented. 



Clausocalanus furcatus (Brady) 



Figures Sj-k, 4a 



Drepanopus furcatus Brady, 1883, pp. 77-78, pi. 4, figs. 1, 2; pi. 24, figs. 12-15. 



Clausocalanus furcatus (Brady).— Giesbrecht, 1888, p. 334; 1892, pp. 186-194, 

 pi. 36, figs. 32, 33, 35.— Dahl, 1894, p. 12.— Cleve, 1900, pp. 56-57.— Farran, 

 1929, pp. 225-226.— Davis, 1950, p. 92 (table).— Wilson, 1950, p. 190.— 



