256 MR. C. TATE REGAN ON THE 
6. XNENOCARA CIRRHOSA. 
Hypostomus cirrhosus Cuv. & Val. Hist. Nat. Poiss., xv. p. 511 (1840); Val. Voy. d’Orbigny, 
Poiss. pl. vil. fig. 3 (1847). 
Ancistrus cirrhosus Kner, Denkschr. Ak. Wien, vil. 1854, p. 272; Eigenm. & Eigenm. Proc. Cal. 
Ac. (2) ii. 1889, p. 47, and Oce. Pap. Cal. Ac. i. 1890, p. 446. 
Chetostomus variolus Cope, Proc. Ac. Philad. 1871, p. 288. 
Chetostomus cirrhosus Giinth. Cat. Fish. v. p. 247 (1864). 
Depth of body 5—5% times in the total length, length of head 2}-2} times. Tead 
1) times as long as broad and 24 times as long as deep. Diameter of eye 63-8 times 
in the length of head, interorbital width 2}—23? times, length of snout 14-13 times. 
Length of mandibular ramus 23-2} times in the interorbital width. Snout with 
tentacles. Interoperculum armed with 9-13 spines, the longest } the length of head. 
23-24 scutes in a longitudinal series, 6-7 between dorsal and adipose fin, 10-12 
between anal and caudal. D. I 7, the first ray equal to 3-} the length of head, 
the last ray, when laid back, nearly or quite reaching the spine of the adipose fin ; 
length of base of dorsal about equal to its distance from middle of spine of adipose 
fin. A. I 4. Pectoral spine extending a little beyond base of ventral (young) or 
nearly to its middle (adult). Caudal obliquely truncate, the lowest ray $-{ the length 
of head. Caudal peduncle 22-24 times as long as deep. Lather large light spots on 
head and body, usually so close together that the ground-colour appears as a network 
of dark lines; fins with dark spots which may be confluent to form cross-bars ; a dark 
spot at the base of the first interradial membrane of the dorsal. 
Total length 140 mm. : 
Eight specimens (including the types of the species): R, Paragnay; R. Amazon ; 
Guiana; ‘Trinidad. 
7. XenocaRa cHAGRESI. (Plate XIV. fig. 7.) 
Ancistrus chagresi Figenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 47, and Oce. Pap. Cal. Ac. 
i, 1890, p. 446. 
Depth of body 5 times in the total length, length of head 2} times. Head 1§-14 
times as long as broad and 1$ times as long as deep. Diameter of eye 7{-8} times in 
the length of head, interorbital width 2} times, length of snout 13 (¢ )-1} ( Q ) times. 
Length of mandibular ramus 23 times in the interorbital width. Snout with tentacles ; 
interoperculum armed with about 10 spines, the longest equal to §-7 the length of 
head. Scutes spinulose, not carinate, 24 in a longitudinal series, 7 between dorsal and 
adipose fin, 11 between anal and caudal. D. 17, the first ray equal to —-2 the length 
of head, the last ray, when laid back, separated by 2 scutes from the spine of the adipose 
tin; length of base of dorsal equal to its distance from the anterior part of the spine of 
the adipose fin. A. I 3-4. Pectoral spine stout, extending a little beyond the base 
of ventral. Caudal obliquely truncate, the lowest ray equal to } (larger specimen)-{ 
