COPEPODA 



8l 



Remarks. In spite of the small differences enumerated in the description, I do not doubt that 

 this species is identical with that described by Sars from Norway, and with that which Wo If end en has 

 described under the name of Pseudactidius from the Fceroe channel. According to my investigations 

 the size of the specimens varied from 3-6 to 4-4 mm., the biggest being those from northern regions; 

 Farran's (1905) specimens measured 3-3 — 3*5 mm., and even 2*65; these small specimens possibly belong 

 to another species. 



17. Chiridius nasutus n. sp. 

 (PL II fig. 4 a; text-figs 18 a*— e). 



1905. pars? Chiridius armatus Boeck. Farran. 



Description. i% Size: Specimen from St. 167 2"88 mm.; anterior division 2*19 mm.; urosome 0-69. 



The shape of the body is in the main like that of the preceding species, but somewhat more 

 slender (text-fig. 18 a). The insertion of the antennulae is apparently better removed from the tip 

 and the rostral spines, which are somewhat longer b c 



and basally swollen, and directed more forwards 

 (text-figs 18 b—c). The anterior division is just three 

 times as long as the abdomen. The genital somite 

 (text-fig. 18 d), which has a receptaculum seminis like 

 that of Ch. armatus, is about 1-5 as long as the third 

 and 17 as long as the fourth somite; the furcal rami 

 are 17 as long as wide and 17 as long as the anal 

 somite; the last segment is about half as long as 

 the third one. The antennulae, which extend some- 

 what beyond the end of cephalothorax, but scarcely to 

 the end of the abdominal somite, have the segments 

 24 and 25 well defined; the measurements differ only 

 in minor details, as the segment 20 is a little longer Text-fig. 18. Ch. nasutus n. sp. 



than 8~o, as the segment 18 is a little longer than a " Head | n dorsal view x 16. b. Rostrum from below X 150. 



J ' => c. Head in lateral view X 60. d. Genital somite etc. X 60. 



21, and as the segment 23 is scarcely I*i as long as e. Pes IV dext. in anterior view with abnormal rami X i5°- 



24. The appendages are like those of Chiridius 



armahis, but the Sp. of the segment 23 extends somewhat beyond the end of the segment 25. The 

 antennae are like those of the preceding species, but the exopodite is 1-5 as long as the endopodite. 

 The mandibulae and maxillae are scarcely different, and the maxillulae only by the smooth anterior 

 surface of the third basipodite. In the maxillipeds the third basipodite is 1-5 as long as the second, 

 and 2*2 as long as the endopodite. The legs are only in minor points different from those of Ch. 

 armatus ; the Se of Re I in the first pair of legs extends a little beyond the end of the second seg- 

 ment, the articulation between the Re I and II of the second pair of legs is well developed anteriorly 

 as well as posteriorly, and its terminal spine has 30—40 spinules (fig. 4 a). A curious difference is 

 found between this species and Chiridms modestus as well as armatus in the arrangement of the 

 glandular pores; in the number of the pores it is, as shown in fig. 4 a, like Ch. modestus, as a single pore 



The Ingolf-Expedition. III. 4. jj 



