free joint is broadly rounded in this species, whereas in Scolecithricella abyssalis, the apex is 

 distinctly pointed. The apical spine on the free joint of Scolecithricella vittata fifth pair is very 

 long. The male is unknown. 



This species has only hitherto been known from the Mediterranean. 



9. Scolecithricella obtusifrons (Sars). Plate XXXI, figs. 1 — 9. 



Amallopliora obtusifrons Sars, 1905 (a), p. 22. 



Scolecithrix emarginata Farran, 1905, p. 36, pi. VII, figs. 6 — 17. 



Amallophora obtusifrons Pearson, 1906, p. 17. 



Scolecithrix obtusifrons Farran, 1908, p. 54. 



Scolecithrix obtusifrons van Breemen, 1908, p. 75, fig. 87. 



Five specimens apparently belonging to this species, were obtained from samples of 

 plankton collected with the Hensen vertical net at the following stations. 



Stat. 141 (1500 metres to surface), 2 specimens. — Stat. 148 (1000 metres to surface), 2 spe- 

 cimens. — Stat. 185 (1536 metres to surface), 1 specimen. 



The specimens agree fairly well with Sars' preliminary description, and also with the 

 figures and description given by Farran (1905). 



The rostrum of the 'Siboga' specimens is furnished with long and moderately stout 

 filaments. The apex of each filament is distinctly bifurcate (Plate XXXI, fig. 4). Length of 

 female 4,3 mm. 



Sars placed the species under the genus Amallophora, but I do not regard the 'Siboga' 

 specimens to be typical members of that genus. 



Scolecithricella obtusifrons has only previously been obtained from the North Atlantic. 



10. Scolecithricella tenuipes (T. Scott). 



Scolecithrix temiipes T. Scott, 1893, p. 48, pi. V, figs. 10 — 19. 

 Scolecithrix tenuipes Giesbrecht & Schmeil, 1898, p. 47. 

 Scolecithrix tenuipes Thompson & Scott, 1903, p. 245. 



One specimen was found in the plankton collected with the Hensen vertical net at 

 Station 141, 1500 metres to the surface. 



Scolecithricella tenuipes is easily distinguished from the other members of the genus by 

 the structure of the fifth pair of feet. The left foot is long and slender and the last joint is 

 spiniform. There is no fringe of hairs on the last joint. The right foot is very short and rudi- 

 mentary. Only the male is known. 



When the female is discovered, this species will probably require to be removed to 

 another genus, as the fifth pair of feet of the male is more closely related to Xanthocalanus, 

 or Neoscolecithrix, than to Scolecithricella. 



Scolecithricella tc7inipes has only been recorded from the Gulf of Guinea and from the Red Sea. 



11. Scolecithricella valida (Farran). Plate XXXII, figs. 1- — 9. 



Scolecithrix valida Farran, 1908, p. 55, pis. V & VI. 



92 



