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free joint is broadly rounded in this species, whereas in Scolectthricella abyssalis, the apex is 
distinctly pointed. The apical spine on the free joint of Scolectthricella vittata fifth pair is very 
long. The male is unknown. 
This species has only hitherto been known from the Mediterranean. 
9. Scolecithyicella bbtusifrons (Sars). Plate XXXI, figs. 1—9. 
Amallophora obtusifrons Sars, 1905 (a), p. 22. 
Scolecithrix emarginata Farran, 1905, p. 36, pl. 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 Amadllophora, but I do not regard the ‘Siboga’ 
specimens to be typical members of that genus. 
Scolecethricella obtusifrons has only previously been obtained from the North Atlantic. 
10. Scolectthricella tenucpes (T. Scott). 
Scolecithrix tenuipes T. Scott, 1893, p. 48, pl. V, figs. 10—I9. 
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. 
Scolectthricella tenutpes 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 Scolectthricella. 
Scolectthricella tenutpes has only been recorded from the Gulf of Guinea and from the Red Sea. 
11. Scolecethricella valeda (Farran). Plate XXXII, figs. 1—9. 
Scolecithrix valida Farran, 1908, p. 55, pls. V & VI. 
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a 
