D. 14(13); A. 13(12); P. 10(11); G.R. 5-6 +1 +11-13, total 17-20; AO 5 (4-6) + 4 (3-5), total 9 (8-10)
Operculum more or less angular posterodorsally, truncate or nearly so posteriorly. Origin of dorsal fin over base of ventral fin. Pectoral fin reaching base of ventral fin (shorter in the Indian Ocean population). Ventral fin long, extending to first or second AOa (just reaching origin of anal fin in Indian Ocean specimens). Base of adipose fin directly over or slightly behind end of base of anal fin.
Vn short, one-half as long as distance between it and So, or even shorter. So small, one-quarter to one-third the size of a body photophores. A separate patch of luminous tissue is usually present in front of the Vn proper in mature males, whereas in oung males(33-36mm) a small, roundish luminous body may develop on top of the Vn; a number of adult males examined had no trace of sexually dimorphic luminous tissue in association with the Vn. However, in adult Indian Ocean males luminous tissue, apparentl originating from the Vn, grows forward to partially or entirely fill the space bordered by the eye, the olfactory organ and the upper jaw.
PLO 1.5-2 times nearer to base of pectoral fin than to lateral line. VLO midway between base of ventral fin and lateral line or a little lower. SAO on a straight or somewhat angular line; SAO3 smaller than rest of organs of same series and 1.5-2 times its diameter below lateral line. AOa1 elevated. Pol under or slightly behind base of adipose fin and 1-2 times its own diameter below lateral line. The luminous scale at PLO is larger and thicker in adult males than in females of comparable sizes.
Fowler, H. W. 1934 
