FISHES OF THE FAMILY LORICABIIDjE. 251 



operculum armed with 4-5 spines. 24-25 scutes in a longitudinal series, 7 between 

 dorsal and adipose fin, 10 between anal and caudal. D. I 8, the first ray equal to 

 f the length of head, the last f as long ; length of base of dorsal equal to its distance 

 from the middle of the spine of the adipose fin. A. I 5. Pectoral spine extending 

 to anterior ^ of ventral or beyond. Caudal obliquely truncate or very slightly 

 emarginate. Caudal peduncle 2-|— 2f times as long as deep. Brownish ; a small 

 dark spot at the base of each dorsal ray ; caudal with small dark spots on the rays. 



Total length 110 mm. 



Three specimens from Villeta, Colombia, collected by Mr. Kay Thomson. 



14. f CH.ETOSTOMUS NUDIROSTRIS. 



Chmtostomus nudirostris Liitk. Vid. Medd. 1874, p. 207; Steind. Denkschr. Ak. Wien, xliii. 

 1881, p. 120, pi. v. fig. 2. 



Evidently closely allied to the preceding species, but with 6-8 interopercular spines, 

 23 scutes in a longitudinal series, I 7 dorsal, and I 4 anal rays. 

 The type, from Valencia, Venezuela, is 95 mm. in total length. 



15. CfLETOSTOJius mickops. (Plate XIV. fig. 3.) 



Hypostornus erinaceus (non Cuv. & Val.) Giinth. Proc. Zool. Soc. 1859, p. 420. 

 Chcetostomus microps Giinth. Cat. Fish. v. p. 250 (1864) ; Steind. Denkschr. Ak. Wien, xlvi. 1882, 

 p. 23; Bouleng. Proc. Zool. Soc. 1887, p. 277. 



Depth of body b\ times in the total length, length of head about 3 times. Head 

 as broad as long and twice as long as deep. Diameter of eye 8-10 times in the length 

 of head, interorbital width of- 3f times, length of snout If times. Interoperculum 

 armed with 10-15 spines. 23-24 scutes in a longitudinal series, 5 between dorsal and 

 adipose fin, 9-10 between anal and caudal. D. I 9 (rarely I 10); the first ray equal 

 to ^ the length of head, the last •§ as loDg; length of base of dorsal equal to its 

 distance from caudal. A. I 3. Pectoral spine extending to or a little beyond base of 

 ventral. Caudal peduncle twice as long as deep. Brownish ; fins with dark spots or 

 bars, a black spot at base of first dorsal ray. 



Total length 80 mm. 



Twelve specimens from Ecuador. 



6. Xenocaka, gen. nov. 



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



Ancistrus (part.) Kner, Denkschr. Ak. Wien, vii. 1854, p. 272. 



Ancistrus (non Gill) Bleek. Ned. Tijd. Dierk. i. 1863, p. 77 ; Eigenm. & Eigenm. Occ. Pap. Cal. 



Ac. i. 1890, p. 444. 

 Chatostomus (part.) Giinth. Cat. Fish. v. p. 240 (1864). 



This genus is distinguished from Ancistrus by the snout with a naked margin, and 



