228 EXPEDITION OF THE "ALBATROSS," 1899-1900. 



Diaphus signatus, sp. uov. 



Plate 3. 



Type 60 mm. long, from the surface at Hydrographic Station 3798 (A. A. 

 27), near Nukuhiva Island, Marquesas Group. 



Most nearly related to Diaphus {Nydoplms) sj^lmdidus Brauer (Zotil. Anz., 

 1904, 28, p. 399, fig. 7), differing in the smaller head and shorter snout, the 

 less elevated interorbital region which scarcely protrudes above the orbital 

 rim, and the more anterior insertion of the ventral fins. The preocular 

 luminous organ is apparently not divided into upper and lower portions, 

 but has immediately above it a distinct luminous dot surrounded by the 

 black pigment. In general proportions, fin rays, and number and distri- 

 bution of photophores, this species does not differ from D. splcndidiis. 



Length of head 28 hundredths of total length without caudal ; diameter 

 of eye 7 ; length of snout 4.3 ; length of maxillary 20 ; greatest depth of 

 body 18; least depth of caudal peduncle 8; distance from snout to front 

 of dorsal, 45 ; to insertion of ventrals 41 ; to front of anal 64 ; to adipose 

 fin 80. 



D. 15; A. 15; P. 12; V. 9 ; lateral line 38; the 11th scale over the 

 supra- ventral photophore, the 18th scale over the upper supra-anal, the 

 25th over the postero-lateral. 



Form slender ; snout short and bluntly rounded, its length little more 

 than balf the diameter of orbit ; maxillary long and slender, not widened 

 posteriorly, its middle well behind tlie pupil ; preopercular margin very 

 oblicjue; gill-rakers slender, 6 + 13 in number on outer arch, the longest 

 three-lmirths the diameter of the eye. 



Pectorals small, inserted low, but little above the level of the ventrals, 

 which they fail to reach. Ventrals inserted well in advance of the dorsal, 

 unusually well developed, their longer inner ra^s extending to base of 

 third or fourtli nnnl ray. The vertical from the last dor.sal rny falls 

 between the vent and the fi-ont of the anal. Last anal ray under the 

 middle of the adipose fin. 



Scales and nuich of the integument lost, but the general color was 



