38 DISCOVERY REPORTS 



at the same time he recorded that a female of 90 mm. had very tiny oostegites. I can see no trace of 

 brood lamellae in any of the Discovery specimens, although four of them measure over 100 mm. 

 I can only conclude that these are immature males. 



G. gigas is a bathypelagic form with a considerable vertical range. Captures by the use of closing 

 nets which, while fishing at great depths, were still far from the bottom, prove that, at any rate 

 when they are immature, the animals occupy levels between 650 m. and nearly 4000 m. The Chal- 

 lenger type and Tattersall's specimen from the Southern Ocean were captured in trawls at 1950 fm. 

 and 1332 fm. respectively, and were presumably living at or close to the bottom. It would appear 

 that, as the animals approach maturity, they occupy lower levels than the young. 



Gnathophausia zoea W.-Suhm, 1873 



1873 Gnathophausia zoea W.-Suhm, p. 400, fig. 



1885 a Gnathophausia zoea, G. O. Sars, p. 44, figs. 



1885 a Gnathophausia willemoesii G. O. Sars, p. 38, figs. 



1891a Gnathophausia sarsii Wood-Mason and Alcock, p. 187. 



1906b Gnathophausia cristata Illig, p. 319, figs. 



1906 Gnathophausia zoea, sarsi Ortmann, p. 42. 



1908 Gnathophausia zoea, Hansen, p. 93, figs. 



1941 Gnathophausia zoea, Fage, p. 34, figs. 



1943 Gnathophausia zoea, Nouvel, p. 15, fig. 



1951 Gnathophausia zoea, Tattersall and Tattersall, p. 82, figs. 



Occurrence : 



St. 245. 10. vi. 27 (day). West of Tristan da Cunha, 2000-1800 m., 1 juv. badly damaged, estimated length 30 mm. 

 St. 1582. 29. iv. 27 (night). East of Zanzibar, 1 900-1 85o(-o) m. 1 juv. 40 mm. 



St. 2064. 3. v. 37 (day). Just north of equator, north-north-east of Ascension I., 1600-1050 m., 1 6*. 7° mm. 

 (Colour note, 'brilliant scarlet'.) 



Remarks. Gnathophausia zoea is one of the commonest species of the genus and it is somewhat 

 surprising that it was only taken at three stations by the ships of the Discovery Investigations. In 

 common with other species of Gnathophausia, very considerable changes occur in the relative 

 lengths of the rostrum and of the postero-dorsal spine of the carapace, which have led workers to 

 regard young specimens of the species as new forms. By a lapsus calami Tattersall and Tattersall, 

 1951, p. 86, give G. bidentata Illig as a synonym of G. zoea. It is, of course, a synonym of 

 G. gracilis. 



Distribution. G. zoea is widely distributed in the tropical and temperate waters of the globe. It 

 has been recorded on many occasions from all parts of the North Atlantic, from Greenland, Iceland 

 and the Faroes in the north ; from the west of Ireland, the Bay of Biscay, off the Azores and Cape 

 Verde Islands in the east; from mid-Atlantic and from the east coast of the United States, the Gulf of 

 Mexico and off Dutch Guiana in the west. In the South Atlantic it has been recorded off the Cape 

 Peninsula in the east and from off the coast of Brazil in the west. Its capture by the ' Discovery ' at 

 station 245 to the west of Tristan da Cunha and in the open ocean to the west of the Gulf of Guinea 

 at station 2064 suggests that it is widely distributed in the South Atlantic. 



It has been recorded from the middle of the Indian Ocean and from the Bay of Bengal and west 

 of Sumatra in the east. Its capture to the east of Zanzibar at station 1582 considerably extends its 

 known geographical range in this ocean. 



There have been many records of the species from the North Pacific, especially in the west from 

 Japanese waters, the China Sea, the Philippines and the East Indian Archipelago. In mid-Pacific it 



