244 ME. C. TATE BEGAN ON THE 



4. Panaque nigrolineatus. 



(-'hatostomus nigrolinealus Peters, Monatsb. Ak. Berl. 1877, p. 471 ; Steind. Denksclir. Ak. Wien, 



xliv. 1881, p. 7. 

 Panaque nigrolinealus Eigenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 44, and Occ. Pap. Cal. Ac. 



i. 1890, p. 426. 



Depth of body 3 \ times in the total length, length of head 2 J times. Head \\ times 

 as long as broad and If times as long as deep. Diameter of eye 7g times in the length 

 of head, interorbital width 1| times, length of snout It? times. Both jaws with about 

 8 teeth on each side. Snout narrowed anteriorly; supraoccipital elevated and arched, 

 with a nearly straight transverse posterior edge ; interoperculum armed with some slender 

 spines, the longest equal in length to the diameter of eye. Scutes spinulose, those of 

 the caudal peduncle carinate, 25 in a longitudinal series, 7 between dorsal and adipose 

 fin, 12 between anal and caudal ; supraoccipital entirely bordered posteriorly by a single 

 scute ; lower surface of head and abdomen completely covered with small granular 

 scales. D. I 7 ; length of base of dorsal nearly equal" to its distance from caudal. 

 A. I 4. Pectoral spine extending to middle of ventral. Caudal obliquely truncate. 

 Caudal peduncle twice as long as deep. Head, body, and fins with undulating longi- 

 tudinal dark brown stripes, which are about as broad as the light interspaces 

 separating them. 



Total length 210 mm. • 



One specimen : Goyaz ; Venezuela. 



5. ClLETOSTOMUS. 



Hypostomus (part.) Cuv. & Val. Hist. Nat. Poiss. xv. p. 489 (1840). 



Chalostoma Tschudi, Fauna Peruana, Pise. p. 25 (1846). 



Chtztostomus Kner, Denkschr. Ak. Wien, vii. 1854, p. 256 ; Bleek. Ned. Tijd. Dierk. i. 1863, p. 78; 



Giinth. Cat, Fish. v. p. 240 (1864) (part.) ; Eigenm. & Eigenm. Occ. Pap. Cal. Ac. i 1890, 



p. 441 (part.). 



This genus is distinguished from Ancistrus by the snout, which has a swollen naked 

 margin. D. I 7-10. A. I 3-5. Vertebra; 5 + 8 + 14 in C. brevis, 5 + 9 + 14 in 

 C. anomalus. 



All the species agree in having the head devoid of ridges or prominences, the supra- 

 occipital and interorbital regions being flat, the sides evenly convex. The snout is 

 broad and rounded ; its naked margin is of moderate width and unprovided with 

 tentacles. The mouth is very wide ; the barbels are small or rudimentary. The scutes 

 are spinulose, not carinate ; the lower surface of the head and the abdomen are 

 naked. 



Andes, extending into Panama and Venezuela. 



