COPEPODA 



83 



(fig. 5 a) the terminal spine has about 80 densely placed, partly fused, spinules; in other respects, except 

 the arrangement of pores, which, except for the more medial position is like that of Ch. obtusifrons 

 etc., the legs are like those of preceding species. 



Occurrence. The S/S. Thor has gathered a few specimens of this species at the following 

 two stations. 



2I / 6 1904. St. 154. 65°27 h. N. 27°io L. W. Yt. ? Wire 3 f ?. 



"/ 7 1904. St. 183. 6i°30 h. N. i7°o8 Iv. W. Yt. 1800 M. Wire 2 f?. 



Remarks. This species, which seems to stand between the species of Chiridius without rostrum 

 and Ch. uasutus, is well characterized by the shape of the rostrum and the position of the glan- 

 dular pores. 



19. Chiridius obtusifrons G. O. Sars. 

 (Plate II figs. 2 a — h ; text-figs 20 a — e). 



1907 

 iqo8 



Chiridius armatus Boeck. Vauhoffen, pp. 519—521. 

 — obtusifrons G. O. Sars. v. Bremen, pp. 34 



—35, fig- 37- 

 1909. nee. Chiridius? obtusifrons G. O. Sars. A. Scott, p. 43, 



pi. XL1V figs 1-3. 

 1913. pars. — armatus Boeck. Stephensen, pp. 316 — 317. 



1S97. Pseudocalauus armatus Boeck. Vauhoffen, p. 279, fig. 6. 

 1900. Chiridius armatus Boeck. G. O. Sars, pp. 29 — 30, pi. XVII. 



1902. — — — Mrazek, pp. 521—22. 



1903. Chiridius obtusifrons n. sp. G. O. Sars, pp. 29— 30, pi. 17. 



1904. — — G. O. Sars. Wolfenden, p. 131. 

 1904? — Vanhoffeni n. sp. Wolfenden, p. 117, pi. IV 



fig- 23. 

 1907. — obtusifrons G. O. Sars. Koefoed & Damas, 



p. 408. 



Description. f$. Size: Specimen from Thor St. 214 measured 4*39 mm.; anterior division 3-12 



mm., urosome 1-27 mm. Sars' specimens measured 4-2 mm. and Vanhoffens 4-5 mm. 



b 



The shape of the body is as figured by Sars 

 (cf. text-fig. 20 a). The articular membrane between 

 the head and first thoracic tergite and between the 

 fourth and fifth thoracic tergite (except in the middle) 

 is often wanting; in the articular membrane be- 

 tween the last thoracic and the first abdominal 

 somite chitinous lists of a rather curious structure 

 are found (text-fig. 20 c). According to most authors 

 no rostrum is observed; in several specimens, ho- 

 wever, the rostrum was represented by a very short 

 spine, sometimes showing trace of bifurcation as a 

 median line, when observed from beneath. The 

 anterior division is 2-4 as long as wide, and 2-4 as 

 long as the abdomen. The genital somite, which 

 has a receptaculum seminis of a similar structure 

 as in Ch. armatus, but more slender, is i - 2 as long 

 as the fourth somite; the f ureal rami are almost 

 twice as long as wide (text-fig. 20 d). 



The antennulae, which almost extend to the 



Text-fig. 20. Chiridius obtusifrons G. O. Sars. 

 a. Cephalosome X 9- b. Genital somite in lateral view X 31. 

 c. Genital somite in dorsal view X 33- d. Anal somite etc. 

 in dorsal view X 60. e. (Downwards to the left) pes II in 

 anterior view X 60. f. (In the middle above) pes III in an- 

 terior view X 60. 



11* 



