3§ 



arched when seen from the side. The rami of the rostrum are slender and sharply pointed, and 

 the excavation is deeper than in the other two species (PI. IV, fig. i 7). The last thoracic spines 

 extend to the end of the genital segment only, and are not greatly chitinized. The proportional 

 lengths of the abdominal segments are very different from ^-Etidetts giesbrcchti. The combined 

 length of the abdomen and furca is slightly more than one-third of the total length of the 

 cefikalothorax, from the forehead to the base of the genital segment. The genital segment is 

 distinctly longer than the combined length of the next two segments. The second, third, and 

 fourth segments are of nearly equal length. The furcal joints are longer than the anal segment, 

 and are about twice as long as broacl. 



Length of female 2 mm. 



ALtideus armatus appears to be widely distributed, if all the records be regarded as 

 correct. Sars in the appendix to the volume on the Calanoids 'Crustacea of Norway', states, 

 that he examined two of the 'Challenger' specimens, and could find 110 difference between them 

 and the Norwegian forms. It was present in the plankton from the Gulf of Guinea, but I was 

 unable to find it in the Ceylon material. 



3. sEtideus bradyi nov. sp. Plate V, figs. 1 — 12. 



Jituleus armatus Brady, 1S83 (pars), p. 76, pi. X, figs. 5 — 16. 

 .l-.tidcus armatus T. Scott, 1893 (pars), p. 70. 

 JEtideus armatus Giesbrecht & Schmeil, 1898 (pars), p. 31. 

 JEtideus armatus Thompson & Scott, 1903 (pars), p. 224. 



Female — length 1,8 mm. 



In general appearance this species resembles ^-Etidctts giesbrechtihwX. it can be distinguished 

 both from that species, and from ^Etideus armatus, by the following characters : - - Viewecl 

 from the dorsal aspect, the forehead is marked by a deep constriction just behind the front 

 margin. A slight expansion is caused by the wide base of the rostrum, and the front margin 

 appears to have a bluntly rounded, knob-like projection. In lateral view, the forehead is boldlv 

 arched, and a distinct chitinized crest is present. The rostrum is very large and horny, with a 

 moderately cleep excavation. The rami are slightly converged at the apex. The last thoracic 

 segment is distinctly chitinized, and is produced into strong spines. The spines project to near 

 the middle of the second abdominal segment. The combined length of the abdomen and furca, 

 is slightly greater than one-third of the total length of the cephalothorax, from the forehead 

 to the base of the genital segment. The genital segment is equal to the combined length of 

 the next two segments. The second and fourth segments are of equal length, but the third 

 segment is distinctly shorter than these two. The furcal joints are about as long as the anal 

 segment, and are fully twice as long as broad. 



The various appendages have a general resemblance to those of the previous species. 



Occurrence - twenty-five specimens of this species were obtained from the plankton 

 collected at the followino- stations. 



o 



Stat. 11S, 2 specimens. - - Stat. 128, 1 specimen. - - Stat. 141, 4 specimens. — Stat. 143, 

 2 specimens. — Stat. 185, 4 specimens. — Stat. 203 (1500 metres to surface), 6 specimens. — 

 Stat. 220 (vertical net), 2 specimens. — Stat. 276, 4 specimens. 



08 



