﻿ICHTHYOLOGICAL RECONNAISSANCE OF COLOMBIA 



21 



ACESTROCEPHALUS Eigenmann. 



Hitherto known from a single specimen preserved in tlie Vienna 

 museum. Allied to Oligosarcus, shaped like Acestrorhynchus. 



Origin of dorsal about midway between snout and caudal. Anal long, 

 its origin below posterior part of dorsal. Snout long, pointed ; maxillary 

 extending to below posterior margin of eye, or further, with a single series 

 of recurved teeth along its entire margin, no canines ; premaxillary with 

 four canines, the first and last in a line with the irregular series of con- 

 ical teeth, the second and third within the outer series (forming a second 

 series) ; dentary with three canines, the third one in a line with a series 

 of small, conical teeth, those in front of the canine separated from it by 

 an interspace and smaller than those behind it which are retrorse ; the two 

 front canines form a second series in front of the series of minute, inner 

 teeth. All the teeth conical. Palatines with a sharp ridge, but without 

 teeth. 



Scales ctenoid. Lateral line complete. Xo rakers on the upper part 

 of the upper gill-arch. 



22. Acestrocephalus anomalus (Steindachner). 



Head 3.66: depth 4.2: D. 11: A. .35; scales 11-75-9; eye a little less 

 than snout, 3.6 in the head. 1 in the interorbital. 



Long and slender, the snout pointed ; no depressions or humps in the 

 profile; postventral area more or less compressed, the preventral area 

 broadly rounded ; dorsal areas rounded ; no distinct median series of scales 

 on back or belly. 



Lower jaw included: fontanels well developed, narrow; third sub- 

 orbital leaving a very wide naked area below, which gradually narrows 

 upward. Many (.33) flat, triangular, recurved teeth on the maxillary; pre- 

 maxillary with four teeth between the first and second canines, three 

 between the second and third, and two between the third and fourth, the 

 first canine the largest ; about nine small, conical teeth in the series behind 

 the two anterior canines, twenty-five or more in the series following the 

 third canine ; canines of the lower jaw about equal to the largest of the 

 upper jaw. Gillrakers very few, 2 + 4, no rakers on the upper three-fourths 

 of the upper arch or the anterior half of the low^er arch. 



Dorsal pointed, equal to head less opercle ; caudal about as long as the 

 head; anal basis long, its margin nearly straight. Yentrals not reaching 

 the anal, pectorals to the ventrals. 



Scales all ctenoid, regularly placed ; fins naked except a series of scales 

 well separated from the scales of the sides, along base of anterior half of 

 the anal ; axillary scale well developed. Lateral line but slightly decurved. 

 complete. 



A narrow silvery band ending in a dark spot on the base of the caudal. 



