316 ME. C. TATE BEGAN ON THE 



15. f Arges prenadilla. 



Brontes prenadilla Cuv. 8s Val. Hist. Nat. Poiss. xv. p. 343, pi. 415 (1840) ; Gunth. Cat. Fish. v. 



p. 224 (1864). 

 Arges prenadilla Steind. Denkschr. Ak. Wien, xlvi. 1882, p. 20, pi. vi. fig. 5. 



Length of head 4 times in the total length, Interocular width equal to the distance 

 from eye to posterior nostril, of times in the length of head. Outer series of teeth of 

 the prfemaxillaries unicuspid ; mandibulary teeth bicuspid ; barbel not extending to 

 the gill-opening. First dorsal ray equal to f-f the length of the head ; pectoral spine 

 extending nearly to base of ventral ; ventrals originating below the fifth dorsal ray, 

 extending beyond the anal opening; adipose fin long, low, without trace of spine. 

 Distance from tip of snout to base of first dorsal ray about 2| times in the total length, 

 from base of last anal ray to the caudal about 4f times. 



The typical example described and figured by Dr. Steindachner is 75 mm. in total 

 length. 



Andes of Ecuador. 



16. Arges fissidens, sp. n. 



Arges ivhymperi (part.) Bouleng. Proc. Zool. Soc. 1890, p. 451. 



Length of head 5 times in the total length. Interocular width equal to the distance 

 from eye to posterior nostril, 3| times in the length of head. Teeth of the outer series 

 of the prsemaxillaries all bicuspid, more or less Y-shaped ; mandibulary teeth bicuspid ; 

 barbel extending a little beyond the gill-opening. First dorsal ray nearly equal to the 

 length of head ; pectoral spine extending to anterior f of ventral ; ventrals originating 

 nearly below the first dorsal ray, extending f-f of the distance from their base to the 

 anal opening ; adipose fin long, low, without trace of a spine. Distance from tip of 

 snout to base of first dorsal ray 3^ times in the total length, from base of last anal ray 

 to caudal 5^ times. Uniform brownish. 



Total length 89 mm. 



Two specimens from the Andes of Ecuador, collected by Mr. Edward Whymper. 



17. Arges fest^e. (Plate XXI. fig. 7.) 



Arges festa Bouleng. Bull. Mus. Torino, xiii. 1898, no. 329, p. 9. 



Length of head 4^-4f times in the total length. Interocular width equal to the 

 distance from eye to posterior nostril, 3^ times in the length of head. Nasal flap 

 produced as a barbel. Lateral teeth of the outer series of the prsemaxillaries 

 unicuspid (rarely bicuspid), median teeth bicuspid ; mandibulary teeth bicuspid ; 

 barbel extending beyond the gill-opening. First dorsal ray nearly as long as the 

 head ; pectoral spine extending to middle of ventral or beyond ; ventrals originating 

 below, or somewhat in advance of the first dorsal ray, extending f of the distance 



