21 



Eucalanus mucronalus when in good condition, is easily distinguished from the other 

 species of Eucalanus by the hook-like projection of the forehead when seen from the side. 

 The forehead of the species hovvever, seems to be easily telescoped, and it is therefore not 

 always possible to make out the beak at first sight. 



4. Eucalanus pileatus Giesbrecht. 



Eucalanus pileatus Giesbrecht, 1888, p. 334. 



Eucalanus pileatus Giesbrecht, 1893, p. 132, pis. n & 35. 



Eucalanus pileatus Giesbrecht & Schmeil, 1898, p. 21. 



Eucalanus pileatus Thompson & Scott, 1903, p. 242. 



Eucalanus pileatus Cleve, 1904, p. 189. 



Eucalanus pileatus Wolfenden, 1905 (a), 996. 



This Eucalanus is apparently not a common species. It was rather scarce in the region 

 traversed by the 'Siboga' as shewn by the records of its occurrence. 



Stat. 16. — Stat. 19. — Stat. 35. — Stat. 36. — Stat. 37. — Stat. 47 1 '. — Stat. 93. — 

 Stat. 96. — Stat. 99. — Stat. ior. — Stat. 106. — Stat. 121. — Stat. 138. — Stat. 165.- 

 Stat. 168. — Stat. 169. — Stat. i77 a . — Stat. 282. — Stat. 315. 



This species has been recorded from the Red Sea, Atlantic, Pacific, and Indian Oceans 



5- 



Eucalanus subcrassus Giesbrecht. 



Eucalanus subcrassus Giesbrecht, 1888, p. 334. 



Eucalanus subcrassus Giesbrecht, 1893, p 132, pis. 11 & 35. 



Eucalanus subcrassus Giesbrecht & Schmeil, 1898, p. 22. 



Eucalanus subcrassus Cleve, 1901, p. 7. 



Eucalanus subcrassus Thompson & Scott, 1903, p. 242. 



Eucalanus subcrassus Cleve, 1903, p. 362. 



Eucalanus subcrassus Cleve, 1904, p. 190. 



Eucalanus subcrassus Wolfenden, 1905(0), p. 996. 



Eucalamis subcrassus although not plentiful, appeared to have a wide distribution in 

 the area traversed. It was noted at the following stations. 



Stat. 35. — Stat. 47''. — Stat. 66. — Stat. 81. — Stat. 89. — Stat. 93. —Stat. 96 (day). - 

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

 Stat. 112. — Stat. 117*. - - Stat. 125 (day). — Stat. 125 (night). — Stat. 129. — Stat. 

 I33 . __ stat. 136. — Stat. 138. — Stat. 141. — Stat. 144. — Stat. 146. — Stat. 148. — 

 Stat. 157 — Stat. 165. — Stat. 168. —Stat. 172. — Stat. 177". — Stat. 184. — Stat. 1S5. - 

 Stat. i89 a . — Stat. 193. — Stats. 194— 7. — Stat. 203 (surface). — Stat. 203 (1500 metres. - 

 Stat. 204. — Stat. 205. — Stat. 217 (horizontal cylinder). — Stat. 220 (vertical net). - 

 Stat. 229. — Stat. 252. — Stat. 315. 



This Eucalanus has also been recorded from the Atlantic, Indian, and Pacific Oceans. 

 and the Red Sea. 



6. Eucalanus subtcnuis Giesbrecht. 



Eucalanus subtcnuis Giesbrecht, 1888, p. 333. 



Eucalanus subtcnuis Giesbrecht, 1893, p. 132, pis. 11 & 35. 



