IC ,4 - COPEPODA 



of the usual structure. The secretory pore at the base of Se Re I is wanting in pes II, present in 

 III -IV. 



Occurrence. The Thor has gathered a single adult female 2 °l(, 1904 St. 88 48°oo, L,. N. 8°3o 

 *h. W. Yt. 300 M. Wire. This species has been recorded from the west coast of Ireland from a depth 

 of about 400 fathoms, from the middle of the South Atlantic between 5 L,. N. and 30 h- S. and from 

 the Malay Archipelagos. 



Though Far ran does not mention the process of the Re II of the antennae nor the lamellous 

 process of the maxillipeds, I do not doubt that the described species is identical with his G. minor \ the 

 mentioned features are found in Wo 1 fen den's species, which he somewhat prematurely proposed to 

 name G. minimus, if it should turn out to be another species than G. minor; the only difference between 

 Wolfendens specimens and mine is the somewhat shorter antennulae, which do not extend beyond 

 the end of the genital somite, and the smaller size (175 — 2 mm.). Between my specimen and Scott's 

 description of specimens from the Siboga Expedition no difference except the shorter antennules of 

 the females from the Siboga Expedition was found. 



27. Gaetanus pileatus Farran. 

 (PI. Ill fig. 6 a; text-figs 26 a — e). 



1903. Gaetanus pileatus n. sp. Farran. p. 16, pi. XVII figs 1 — 11. 



1904. — caudani Canu. Wolfenden, p. 114, pi. IX, figs 



20—22. 



1905. — pileatus Farr, Farran, p. 33. 



1905. — caudani Canu. G. O. Sars, p. 4. 



1906. — — — Pearson, p. 13. 

 1908? — — Wolfenden, p. 31. 



1908. Gaetanus caudani Canu. v. Bremen, p. 42, fig. 48. 



1908. — pileatus Farr. Farran, pp. 35—36. 



1909. — caudani Canu. A. Scott, pp. 46 — 47, pi. VIII 



figs 9-15. 

 1911. — pileatus Farr. Wolfenden, pp. 229 — 231, taf. 27 



figs. 1 — 2, textf. 17 a — c. 





Description. f$. Size: Specimen from St. 82 measured 574 mm.; anterior division (including 

 frontal spine 0-4 mm.) 47; urosome 1-04 mm. 



The frontal spine has, as seen in (text-fig. 26 a) and as described by the authors, a very charac- 

 teristic shape; the frontal organ is rather indistinct; the rostrum, which is very short, is in some spec- 

 imens undivided, in others terminally slightly bifurcate. The fourth and fifth thoracic somites show 

 dorsally trace of segmentation. The lateral spines are rather suddenly produced, slightly divergent, 

 and almost reach the end of the genital somite. The anterior division is distinctly 4 times as long as 

 the urosome, the genital somite is distinctly produced below, and the structure of the receptaculum 

 etc. is in lateral view like that of G. latifrons (cf. fig. 5 b). 



The relative length of the abdominal somites and the caudal rami, which are almost as long 

 as wide, is 42, 23, 19, 19 and 20. 



The antennulae extend 6—7 segments beyond the end of the abdomen. The measurements 

 provide some similarity to Gaetanus miles, but differ especially by the more slender distal segments; 

 the segment 19, which is the longest segment, is twice as long as segment 2, 17 as long as segments 

 80^9 and 1-2 as long as segment 22; the segment 19 is 2*3 as long as segment 24. In the antennae 

 the Re is only n as long as Ri, and the Ri I is 2 - 5 as long as Re II, which only possesses a terminal 

 seta, and is only a trifle shorter than the Re VII. The maxillulae possess no spinules on the posterior 



