426 CALIFORNIA ACADEMY OF SCIENCES. 



395. Panaque nigrolineatus. 



. Chcetosiomus niyrolinealus Peters, MB. Ak. Berl. 1877, 471 (Calabozo); 



Steindachner, Flussf. Siidam. iii, 7, 1881 (Orinoco, near Ciu- 



dad, Bolivar). 



Panaque nigrolinealus Eigenm. & Eigenm. I.e. (Goyaz). 

 Habitat: South Central Brazil; Central Venezuela. 



Short and heavy, the depth one-fifth less than the 

 width, which is about 3 in the length. Caudal peduncle 

 comparatively slender, its depth equal to one-third of 

 the greatest depth. 



Head large, its width at the opercles about equal to 

 the length of the snout and orbit; profile rather straight 

 from tip of snout to the eye, the occiput strongly arched; 

 a depression above the eyes; a broad blunt ridge from 

 the eye forward; occipital bone truncate behind, mar- 

 gined by a single, large nuchal plate; temporal shield 

 forming the posterior and half the upper margin of the 

 orbit. Snout rather pointed, entirely granular; the ex- 

 treme tip sometimes naked. 



Orbit 5 in the snout, 7J in the head, 4 in the inter- 

 orbital. Lower surface of the head granular; lips with 

 short thick papillae; teeth large, broad-tipped. 



Preopercle large, its bristles slender, the longest vary- 

 ing from 1-2 diameters of the orbit in length. Region 

 between eye and gill-opening entirely granular. 



Humeral ridge obtuse; the lateral scutes with short 

 marginal spines which are largest and most numerous 

 on the tail and on the uppermost and lowermost series. 

 Ventral surface entirely granular. 



Distance of the dorsal fin from tip of snout about 2 in 

 the length. Base of dorsal fin equals its distance from 

 the base of the middle caudal rays. 



Caudal obliquely truncate, the central rays 2 in the 

 head. Anal short, placed under the interspace between 

 the dorsal and adipose fins. 



Ventrals inserted under the first dorsal ray, reaching 

 beyond base of anal. 



