minute dots of whitish tissue anterior to Vn is not bulged upward above these dots, or at best 

 any bulges are extremely minute and difficult to perceive. Also, D. similis has a scale of 

 luminous tissue only at PLO, and has fewer gill rakers. AOa, is seldom elevated to the level of 

 SAO;;, and the last AOa is somewhat less elevated than that of £>. trachops. 



Size: To about 72 mm. 



Least depth of capture: To about 170 m at night. 



Distribution: D. similis is known only from a small area of the eastern tropical Pacific 

 Ocean bounded by about 04°-10° N, 87°-119° W (Fig. 88, open circles). 



Diaphus trachops 



Wisner, 1974 



Fig. 91 — Diaphus trachops, holotype, 63.5 mm. From Wisner (1974, p. 5, fig. 2). 



Description 



D. 14; A. 15 (14-16); P. 12 (11-13); AO 6 (5-7) + 5-6, total 11 (10-12); gill rakers 8 (7-9) -^ 1 

 -I- 15-16 (14-17), total 24-25 (22-26); vertebrae 34-35. 



Dn small, round, deeply recessed. Vn prominent, triangular, about twice as large as Dn 

 and protruding into orbital rim. The luminous tissue of Vn is vertically striated. Anterior to 

 Vn, and embedded in a band of dark tissue, are 4 or 5 minute dots of whitish tissue (probably 

 luminous); the pigmented tissue above these dots bulges upward in small domes that protrude 

 slightly above orbital rim (Fig. 90 A) and are evident in specimens as small as 22 mm, but not 

 in one of 15 mm. These protrusions, although much less prominent, resemble those that project 

 notably from the Vn into the orbital rim o{ Diaphus luetkeni. AOa, elevated to level of SAO2; 

 last AOa elevated to a line through VO3, SAOj, and AOa,. PLO slightly below midway be- 

 tween lateral line and pelvic origin. Small scales of luminous tissues immediately posterior to 

 PLO, VLO, SAO:,, Pol, and Prc4. 



Size: To about 64 mm. 



Least depth of capture: To 100 m at night. 



Distribution: Most specimens have been taken near Oahu, Hawaii (Fig. 87, solid circles). 

 One specimen known from near Monterey, California (not shown in Fig. 87), may be a stray. 



106 



