148 COPEPODA 



The first pair of legs (text-fig. 40 b) has the articulation between Re I and II better developed 

 than in the preceding species, but is in other respects scarcely different; the terminal spine of the second 

 pair of legs has 90 teeth, and the second basipodite of the fourth pair of legs has n knife-shaped 

 spines (fig. 5 d). 



The outline of the labrum is, as seen in text-fig. 403, somewhat different from that of Ch. Streetsii; 

 the oral surface of the labrum differs in the same way as that of Ch. pustiilifera from that of Ch. Streetsii. 

 The lamina labialis is smooth, and the area in front of it is, as shown in fig. 5 e, somewhat different 

 from that of Ch. Streetsii, and so is the arrangement of hairs upon and behind the labial lobes (fig. 

 5 f), the main difference being that a large group of delicate hairs is found where the series III and 

 IV start at the base of labial lobes, not where series IV and V start. In front of the oesophagus a 

 long coecal sac is found. 



Occurrence. Of this species the S/S Thor has only taken 4 adult females "/ 7 1904 St. 183 6i3o 

 L,. N. I7o8 L,. W. Yt. 1800 M. Wire. 



Remarks. This species is very nearly related to Ch. pustulifera, and ought, accordingly, to be 

 referred to the same genus. It shows some similarity to U. obtusa G. O. Sars (1905 p. 13; Farran 1908 

 p. 40), which has the antennules "depassant a peine, en longueur, la division anterieure du corps", as 

 well as to U. lobata G. O. Sars (1907, pp. n 12), from which it seems to differ by lateral corners "assez 

 saillants en arriere et etroitement arrondis an bout", by longer abdomen and antennulae. 



43. Chirudina notacantha G. O. Sars. 

 (PI. V figs 7 a b; PI. VI figs i a b; text-figs 41 a k). 



1905. Gaidius notacanthus n. sp. G. O. Sars, pp. 910. 

 1908. G. O. Sars. Farran, pp. 3334, pi. 



Ill fig. 7. 



1909. Nee. Gaidius notacanthus G. O. Sars. A. Scott, p. 52, pi. 



XXI figs 2432. 



Description. Y^ (St. V). Size of a young male 572 mm.; anterior division 4-7 mm.; tirosome 

 1-02 mm. Young females measured from 4-315-54 mm. Sars' specimen measured c. 5 mm. 



The lateral outline of the head is gradually sloping towards the strong undivided rostrum, 

 which is directed downwards and slightly backwards (text-fig. 41 g). The cephalosome, which in the 

 middle is scarcely half as broad as it is long, is attenuated towards the front as well as towards the 

 end. The head is well separated from the first thoracic tergite, and the fifth one is well marked out 

 in front (text-fig. 41 i); the latter somite is, near dorsal margin, produced into a strong triangularly 

 pointed spine, which scarcely attains the end of the first abdominal somite. The abdomen, which is 

 scarcely one fourth as long as the anterior division, has four somites, the comparative length of which 

 was 22, 29, 21, 17 and 15 (furcal branch); the furcal branch is distinctly wider than long. Along the 

 hinder margins densely placed hairs are found; the terminal setae are distinctly shorter than the ab- 

 domen (text-fig. 41 j). 



The antennulae extend almost to the middle of the abdomen; in measurement they are very 

 much like those of Ch. Streetsii. The exopodite of the antennae is almost r8 as long as the endopo- 

 dite, which has 7 setae in Li and 6 in L,e; the first segment of the exopodite has a short process 

 inside, bearing a delicate seta, only as long as the process itself, and the second has a terminal seta 



