structure. There are five pairs of swimming feet in both sexes. Each pair is composed of a 

 three-jointed endopodite and exopodite. The joints of the basiopodite of the fïrst feet are, 

 however, distinct from those of true Ca/anus. The apex of the anterior margin of the fïrst joint, 

 terminates in a well defined hook-like projection. The second joint is furnished with a strong, 

 naked, pyriform spine, on its anterior surface. The base of this spine, is only slightly attached 

 to the surface of the joint. A considerable portion of the spine is continued upward, into a 

 distinct tooth-like process, resulting, with the combination of the hook on the first joint, in the 

 formation of a feeble prehensile apparatus. The other pairs of feet in the female are of the 

 normal Calanus type, except that the first joint of the basiopodite of the fifth pair is not serrate 

 on the inner margin. The fifth pair of feet in the male has a distinct prehensile left exopodite. 

 The endopodite of that side is three-jointed, rudimentary, and destitute of plumose hairs. The 

 right foot is normal. The first joint of the basiopodite resembles that of the female in not 

 being serrate on the inner margin. 



Remarks. The type of the genus is Ca/anus pauper Giesbrecht, but the structures on 

 the joints of the basiopodite of the first feet, and the character of the male left fifth foot, 

 with its prehensile exopodite and the rudimentary, naked, three-jointed endopodite, distinguish 

 Canthocalanus from true Calanus. The genus at present is represented by one species. 



i. Canthocalanus pauper (Giesbrecht). 



Calanus pauper Giesbrecht, 1888, p. 331. 



Calanus pauper Giesbrecht, 1S93, p. 91, pis. 6 & 8. 



Calanus pauper Giesbrecht & Schmeil, 1898, p. 16. 



Calanus pauper I. C. Thompson, 1900, p. 275. 



Calanus pauper Cleve, 1901, p. 5. 



Calanus pauper A. Scott, 1902, p. 400. 



Calanus pauper Thompson & Scott, 1903, p. 241. 



Calanus pauper Cleve, 1903, p. 357. 



Calanus pauper Wolfenden, 1905 (a), p. 995, pi. XCVII, figs. 29 — 35. 



Canthocalanus pauper appeared to be generally distributed throughout the area investigated 

 by the 'Siboga' and was noted at the following stations. 



Stat. 16. — Stat. 37. — Stat. 47''. — Stat. 50. — Stat. 66. — Stat. 71. — Stat. Si. — 

 Stat. 93. — Stat. 96 (day). — Stat. 96 (night). — Stat. 98. — Stat. 99. — Stat. 101. — 

 Stat. 106. — Stat. 109. — Stat. 1 10. — Stat. 112. — Stat. 11S. — Stat. 121. — Stat. 125 

 (night). — Stat. 128. — Stat. 133. — Stat. 136. — Stat. 141. — Stat. 142. — Stat. 143. — 

 Stat. 144. — Stat. 148. — Stat. 149.— Stat. 165.— Stat. 168. — Stat. 169. — Stat. 172.— 

 Stat. 184. — Stat. 185. — Stat. 186. — Stat. 189". — Stats. 194—7- — Stat - 20 3 (1500 

 metres). — Stat. 204. — Stat. 205. — Stat. 214. — Stat. 215 1 . — Stat. 217 (horizontal 

 cylinder). — Stat. 224. — Stat. 225. — Stat. 229. — Stat. 252. — Stat. 271. — Stat. 276. — 

 Stat. 282. — Stat. 315. 



The distribution of this species, so far as is known at present, seems to be limited to 

 the Mediterranean, Gulf of Suez, Red Sea, Arabian Sea, Indian and Pacific Oceans. Wolfenden, 

 1905 («), has described and figured the characteristic parts of this copepod from specimens 

 collected around the Maldive Islands by J. Stanley Gardiner. These figures agree well with 

 the original ones given by Giesbrecht. 



9 



SIHOGA-EXrEDITIE XXIX a. 2 



