82 



COPEPODA 



was found in the three segments of the exopodites in the three last pair of legs, but in the position 



of the pores, especially in Re I- — II, it is most like Ch. armatus, as these are placed on the anterior 

 surface, well removed from the lateral margin. 



Occurrence. This species was taken by the S/S Thor at the following 3 stations viz: 



"/ 7 1904. vSt. 183. 6i°3o L. N. i7°o8 h. W. Yt. 1800 M. Wire 1 f $. 

 8 / 6 1905. St. 72. 57°52 L. N. 9^3 h. W. Yt. 1500 M. Wire 2 f$. 

 V 9 1905. St. 167. 57°46 L. N. 9°55 L. W. Yt. 1500 M. Wire 2 f ?. 



Remarks. This species, which on account of its small size, the prominent rostrum, and the 

 curious arrangement of the secretory pores is well distinguished from Ch. armatus, is certainly new 

 to science, as in the literature I have only found a single reference to a species of the Ch. armatus 

 type of a size of 2*65 mm. (viz. Far ran 1905 p. 34). 



18. Chiridius modestus n. sp. 

 (PI. II fig. 5 ; text-figs 19 a — c). 



Description. f°j. Size: Specimen from St. 183 measured 3-69 mm.; anterior division 270 mm., 

 urosome 0-99. 



The rostral spines are longer and more prominent than in Ch. armatus, but less so than in 

 nasutus (text-fig. 19 b). The outline of the head is anteriorly not fairly rounded as in Ch. armatus, but 



distinctly produced (text-fig. 19 a). The frontal organ is prominent, 

 and the distance between it and the base of the rostrum is short 

 and straight, not slightly concave as in the two other species. The 

 cephalothorax, which is 2*5 times as long as wide, is scarcely 3 

 times as long as the urosome. The genital somite, which has a 

 receptaculum seminis of the usual structure, is about 1-3 times as 

 long as the third somite, and 17 as long as the fourth (text-fig. 19 c); 

 the furcal rami are i-6 as long as wide, and 1-4 as long as the 

 anal somite, which is a little longer than the furca; the latter 

 somite is scarcely half as long as the third one. 



The antennulae, which extend somewhat beyond the end 

 of the thorax, have the 24 — 25 segments almost fused. The ap- 

 pendages and the measurements are scarcely different from those 

 of Ch. nasutus. The antennae have the exopodite 1-4 as long as 

 the eudopodite; the Re I has, inwards, a conical process, but no seta, and the Re II has a medial and 

 a terminal seta placed on a small protuberance, in addition to a basal protuberance without seta. The 

 mandibulae and maxillae do not show any feahtres of interest, and the maxillulae only differ from 

 those of Ch nasutus by slightly developed spinulation of the anterior surface of the Li 3. The third 

 basipodite of the maxillipeds is 14. as long as the second, and 2*4 as long as the eudopodite; its 2 

 proximal setae are placed near to each other with the articular membranes confluent. The Se Re I 

 in the first pair of legs extends distinctly beyond the end of the segment. In the second pair of legs 



Text-fig. 19. Chiridius modestus n. sp. 



a. Head in dorsal view X J 6. 



b. Head in lateral view X 60. 



c. Genital somite etc. X 60. 



