COPEPODA 



to fifth groups consist of an inner more or less longitudinal row of fairly long setae inwards and of 

 more irregularly placed setae laterally; a sixth group of very short delicate setae is found; the trans- 

 verse rows are, as seen in figs, like those of Chirudina Strcctsii. The lamina labialis (PL VI fig. i b) is 

 not quite like that of any of the examined species, as it consists, as shown in figure, of two rather 

 independent portions. The arrangement of the setae in front of the row is like that of Chirudina Streetsii, 

 but no granular area was observed. The arrangement of the series upon and behind the labial lobes is 

 in its main feature like that of C. abyssalis (PL VI fig. i b ; cf. PL V fig. 5 f). Laterally a similar tuft 

 of hairs is found as in Ch. piistulifera. 



i$ (St. VI). Size of specimen from Thor St. 183 was 67 mm.; anterior division 5-2 mm.; urosome 1-5 mm. 



The head is rounded, with fairly slender rostral spine (text-fig. 41 a). The body is more slender 

 than in the female ; the articulation between the head and the first thoracic tergite is only indistinct ; 

 the lateral spine of the thorax is placed more dorsally, is more slender and apparently starts from the 

 fifth somite. The comparatively slender abdomen is about one third of the anterior division, and has, as 

 seen in text-fig. 41 b, the genital opening on the left side, and has a seam of short, delicate teeth along 

 the posterior margins of somites II IV. The furcal rami are somewhat wider than long; the St. 2 is 

 somewhat longer than the abdomen. The antennulae extend about to the end of the second abdominal 

 somite; the segment 10 is partly fused with 8039, the segment 12 with 13, but the segments 21 and 

 22 are well separated on both sides; "JBsthetasken" are only wanting in segments 20, 23 and 24; the 

 measurements are very similar to those of the young ones. The exopodite of the antennae is only 1-3 

 as long as the endopodite; the Re I and II are indistinctly separated, and both possess a rudimentary 

 setigerous process, but the antennae are in other respects like the female. The inandibula scarcely 

 differs from that of Ch. Slreetsii. The maxillulae possess in Li i at least 10 soft-skinned ringed appen- 

 dages as well as two short setae of usual structure, in Li II, which is fairly long, 3 soft appen- 

 dages, and in Li III 5 setae of usual structure are found; the basipodite III has 5 setae, the Ri I II 

 have 7 setae, and the Ri III has 7 as well; the exopodite has 10 long setae and a short delicate inner 

 one, and the Le has 2 short basal ones and 5 long distal ones. The maxillae are soft-skinned, but they 

 are better developed than in most other species of this family; the Lob. I IV are well developed, and 

 possess 2 to 3 setae, and so does Lob. V, but its Sp. is strong and not twisted ; the Re has 6 setae. The 

 maxillipeds are in main feature like those of Ch. Streetsii; their third basipodite is 2-5 as long as Ri 

 and 1-5 as long as the two basal segments. 



The first pair of legs has the articulation between Re I II better developed, and the Se Re I 

 is quite rudimentary ; the three last natatory legs are scarcely different from those of the young specimens. 



The right fifth foot has a rather short third basipodite; the right endopodite has some similarity 

 to that of Ch. Streetsii, is terminally gutter-shaped on the anterior surface, but has somewhat proximally 

 to its end laterally a rounded incision (text-fig. 41 c); the outline of the endopodite is rather irregular, but 

 no marginal laminae or teeth were observed in proximal half. The right exopodite has the two first 

 segments fused, and is, observed from in front, distinctly convex towards the middle; the third segment 

 is obtusely rounded, is rather elongate and possesses marginally a distinct lamina (text-figs 41 c d). The 

 third basipodite of the left foot is long, almost attaining the middle of Re I ^ II ; the left endopodite 

 (text-fig. 41 e) is unsegmented, and is, as shown in fig., distinctly narrow somewhat beyond the middle. 



