2 43 



Stat. 143 (HENSEN vertical net, 1000 metres to surface), 2 specimens. -- Stat. 148 (HENSEN 

 vertical net, 1000 metres to surface), 2 specimens. 



Oncaea tenuimana can be recognised by the rather long abdomen and comparatively 

 short furcal juints. 



This species is evidently rather limited in its distribution. It does not appear to have 

 been recorded by any other observer since Giesbrecht described it from specimens found in 

 plankton collected in the Pacific Ocean. 



5. Oncaea venus/a Philippi. 



Oncaea venusta Philippi, 1843, p. 62, pi. 4. 



Oncaea venusta Giesbrecht, 1893, p. 590, pis. 2, 3 & 47. 



Oncaea venusta I. C. Thompson, 1900, p. 286. 



Oncaea venusta Wheeler, 1900, p. 190, fig. 27. 



Oncaea venusta A. Scott, 1902, p. 418. 



Oncaea venusta Thompson & Scott, 1903, p. 284. 



Oncaea venusta Cleve, 1903, p. 366. 



Oncaea venusta Cleve, 1904, p. 194. 



Oncaea venusta Wolfenden, 1905 (a), p. 1029. 



Oncaea venusta Pearson, 1906, p. 34. 



Oncaea venusta Norman & T. Scott, 1906, p. 197. 



Oncaea venusta van Breemen, 1908, p. 186, fig. 198. 



This proved to be the most common and widely distributed member of the genus in the 



area investigated by the 'Siboga'. It was present in the plankton collected at the following stations. 



Stat 16. — Stat. 35. — Stat. 36. Stat. ^. — Stat. 40. Stat. 47 1 '. — Stat. 50. — Stat. 66. — 

 Stat. 71. — Stat. 75 (HENSEN vertical net, 1 1 metres to surface). — Stat. 81. — Stat. 89. — 

 Stat. 93. — Stat. 96 (day). — Stat. 98. — Stat. 99. — Stat. 10 1. — Stat. 110. — Stat. 112. — 

 Stat. 118 (HENSEN vertical net, 900 metres to surface). — Stat. 121. — Stat. 122. -- Stat. 

 125 (day). — Stat. 128 (HENSEN vertical net, 700 metres to surface). — Stat. 133. — Stat. 136. — 

 Stat. 138. — Stat. 141 (HENSEN vertical net, 1500 metres to surface). — Stat 142. — Stat. 143 

 (HENSEN vertical net, 1000 metres to surface). — Stat. 144. — Stat. 148 (HENSEN vertical 

 net, 1000 metres to surface). — Stat. 157. — Stat. 165. — Stat. 168. — Stat. 169. — Stat. 

 184. — Stat. 185 (HENSEN vertical net, 1536 metres to surface). ■ — Stat. 186. — Stat. 193. — 

 Stat. 194 — 7. — Stat. 203 (surface). — Stat. 203 (HENSEN vertical net, 1500 metres to 

 surface). — Stat. 205. — Stat. 210'. — Stat. 213. — Stat. 216. — Stat. 217 (horizontal 

 cylinder). — Stat. 220 (surface). — Stat. 220 (HENSEN vertical net, 200 metres to surface. — 

 Stat. 223. — Stat. 224. — Stat. 229. — Stat. 243 (HENSEN vertical net, 1000 metres to 

 surface. — Stat. 252. — Stat. 271. — Stat. 276 (HENSEN vertical net, 750 metres to sur- 

 face. — Stat. 282. — Stat. 304. — Stat. 315. 



Oncaea venusta can readily be separated from the other members of the genus by the 

 comparatively long furcal joints. The furcal joints are longer than the combined length of the 

 third and fourth abdominal segments. 



This species is widely distributed in the warm regions of all the great oceans. 



Genus Conaea Giesbrecht, 1891. 



This genus is closely related to Oncaea, but it is readily separated by the long end 

 joint of the antennae with its armature of very long and slender curved spines. 

 One species was represented in the plankton collected by the 'Siboga'. 



2 43 



