gilbert: the lantern-fishes of japan 93 



of the fifth ventral. Upper supra-anal immediately below the lateral line, the 

 posterolateral and the upper precaudal slightly below its level. Antero-anals 

 about equally spaced, the first above and anterior to the second, less elevated 

 than the middle supra-anal. Last antero-anal elevated, nearly midway between 

 its predecessor and the posterolateral, but a trifle behind the line joining the 

 two. The remaining four posteroanals form a gently curved line which rises 

 slightly posteriorly. Postero-anals five (six in one cotype). Precaudals forming a 

 gently curved line nearly parallel with base of lower caudal lobe, the upper 

 spots more widely spaced than the lower two. 



General color dusky; lining of mouth and gill cavity black, the opercle with 

 blue-black reflections. A black area above each eye. A dusky band across the 

 mandible below eye. Fins with minute dark specks. 



Three cotypes from the same locality as the type; the latter is deposited 

 in the U. S. National Museum. 



20. Diaphus gigas sp. nov. (Plate XII, fig. 2.) 



Type 172 mm. in total length, 140 mm. to base of caudal, from Sagami 

 Bay; collection of Alan Owston (C. M. No. 4601). 



Most nearly related to D. chrysorhynchus Gilbert and Cramer and D. 

 perspicillatus Ogilby. From both species it differs in the greater development of 

 the inferior pre-orbital, which is produced dorsally well beyond the small tri- 

 angular superior pre-orbital. It differs further from D. perspicillatus in the lower 

 position of the third ventral photophore, and from D. chrysorhynchus in the 

 lower suprapectoral and in the restriction of the inferior pre-orbital to the por- 

 tion of the lower orbital rim in advance of the pupil. In D. chrysorhynchus, it 

 extends to below the posterior margin of the pupil. 



Brauer's description and figure of D. elucens (Die Tiefsee Fische, pp. 219, 

 220), fails to indicate any difference from D. perspicillatus, with which it is 

 probably identical. 



Measurements in hundredths of length without caudal: Length of head 29; 

 diameter of eye 8.5; length of snout 3.8; frontal width at middle of eyes 10; 

 length of maxillary 19.5; distance from eye to end of maxillary 11; depth of 

 body 20; of caudal peduncle 8.5; distance from tip of snout to front of dorsal 

 42; to base of ventrals 43.5; to last dorsal ray 62.5; to front of anal 63.5; to 

 last anal ray 81; to adipose dorsal 80. Length of pectorals 13; of ventrals 18. 



Dorsal rays 15 (2 rudiments); anal rays 15 (2 rudiments); ventral rays 9 

 (1 rudiment); pectoral rays 11. Scales of lateral line 35, the upper supra-anal on 

 the 18th scale, the posterolateral on the 25th. Gill-rakers long, 8 -f- 16. 



