108 
tely behind it the long anal. On each side of the base of the 
dorsal and anal, between two following rays, a short, curved, 
spine-like process, belonging to the ray in front of it, from 
the base of which it develops. Most rays of dorsal and anal 
simple. Teeth in intermaxilla and mandible large, quadrangular, 
bicuspid, depressible, arranged in groups, increasing in each 
group in size from forward to backward, those in the maxilla 
small, close-set. A few teeth on vomer, palatines and tongue. 
A postorbital revolving luminous organ. On each side a ven- 
tral series of fixed organs, from isthmus to caudal; a lateral series 
from gillopening to middle of anal, besides numerous ones 
scattered on head and body. Four gills. No pseudobranchiae, 
nor gillrakers. Branchiostegal rays numerous. 
1. Idiacanthus fasciola Ptrs. 
Idiacanthus fasciola Peters, Monatsber. Akad. Berlin, 1876, p. 847. 
Idiacanthus fasciola Brauer, Deutsche Tiefsee-Exp. Tiefseefische, 1906, p. 60. 
Idiacanthus fasciola Max Weber, Siboga-Exp. Fische 1913, p. 15. 
Fig. 37. ldiacanthus fasciola Ptrs. (after Brauer). 
B. 15—16; D. 63—67; A. 40—45; V. 6. 
Height 40—45, head more than 14, eye about 5'/, or more. 
Snout equal to eye or shorter, on the interorbital space two 
diverging crests. Barbel twice as long as head. Origin of dorsal 
nearer to ventrals than to posterior margin of head. Ventrals 
shorter than head. Intermaxillary with 13—15 unequal teeth, 
