i.6s 



Stat. 16. — Stat. 19. — Stat. 35. — Stat. 37. — Stat. 40. ■ Stat. 50. — Stat. 66. — 

 Slat. ;-; (HENSEN vertical net, 11 metres to surface). - Stat. 81. - Stat. 93. — Stat. 96 



(day). — Stat. 96 (night). -- Stat. 98. — Stat. 99. — Stat. 101. - Stat. 106. - Stat. 109. 



Stat. 112. — Stat. 117", 200 specimens. — Stat. 122. Stat. 124, 441, specimens. 



Stat. 125 (night). Stat. 136. — Stat. 138. — Stat. 141 (Mensen vertical net, 1500 



metres to surface). — Stat. 142. — Stat. 144. — St.it. 146. — Stat. 148 (HENSEN vertical 



net, 1000 metres to surface). — Stat. 157. — Stat. 165. — Stat. 169. -- Stat. 172. 



Stat. 174. - Stat. 177". — Stat. 184. — Stat. 189' 1 . — ■ Stats. 194 — 7. — Stat. 203 (sur- 

 face). — Stat. 204. — Stat. 205. — Stat. 213. — Stat. 214. — Stat. 215 1 . — Stat. 220 



(HENSEN vertical net, 200 metres to surface). — Stat. 223. — Stat. 224. - - Stat. 225. 



Stat. 229. — Stat. 245. — Stat. 252. — Stat. 276 (HENSEN vertical net, 750 metres to 

 surface). — Stat. 282. — Stal. 304. — Stat. 315. 



Labidocera acuta is readily distinguished by the presence of a median crest on the forehead, 

 and by the structure of the fifth pair of feet of both sexes. 



This species appears to have a fairly wide distribution in the warm regions of all the 

 great oceans. 



2. Labidocera detruncata (Dana). 



Pontella detruncata Dana, 1849, p. 29. 



Pontellina detruncata Dana, 1852, p. 1 143, pi. 80. 



Pontella detruncata Brady, 1883, p. 90,' pis. XXVI & XLV. 



Labidocera detruncatum Giesbrecht, 1893, p. 445, pis. 23, 25 & 41. 



Labidocera detruncata Giesbrecht & Schmeil, 1898, p. 135. 



Labidocera detruncata Thompson & Scott, 1903, p. 251. 



Labidocera detruncata Wolfenden, 1905 (a), p. 1017, pi. XCVIII. 



This Labidocera appeared to be rather rare and the distribution was very limited in the 

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

 eieht stations. 



Stat. 16, 10 specimens. — Stat. 96 (night), 5 specimens. — Stat. 98, 3 specimens. — Stat. 

 1 10, 20 specimens. — Stat. 111, 10 specimens. — Stat. 203 (surface), 7 specimens. — 

 Stat. 282, 4 specimens. — Stat. 315, 5 specimens. 



Twenty-four females and forty males were obtained. 



Labidocera detruncata is only known from the Indian and Pacific Oceans. 



3. Labidocera kroycri (Brady). 



Pontella kroycri Brady, 1S83, p. 93, pi. XXXIX, figs. 1 — 19. 



Labidocera kroyeri Giesbrecht, 1893, p. 446, pis. 23, 25 & 41. 



Labidocera kroyeri Giesbrecht & Schmeil, 189S, p. 135. 



Labidocera kroyeri Cleve, 1901, p. 7. 



Labidocera kroyeri Thompson & Scott, 1903, p. 251. 



Labidocera kroyeri Pearson, 1906, p. 30. 



Labidocera kroyeri van Breemen, 1908, p. 15 1. 



Labidocera kroycri, although represented by fewer specimens, appeared to be more widely 

 distributed than Labidocera detruncata. Seventeen females and nine males were obtained from 

 the plankton collected at the following fourteen stations in the area investigated by the 'Siboga'. 



165 



