236 MR. C. TATE REGAN ON THE 
connected by a membrane to the 3 scutes following it. Length of base of dorsal a 
little more than its distance from the caudal. A.1I4. Pectoral spine extending to 
middle of ventral. Caudal obliquely and weakly emarginate or truncate. Caudal 
peduncle about 2% times as long as deep. Large round white spots on head, body, 
and fins. 
Total length 280 mm. 
‘Two specimens, stuffed (types of the species): R. Araguay; R. Tocantins. 
20. fANCISTRUS PUNCTATISSIMUS. 
Chetostomus punctatissimus Steind. Denkschr. Ak. Wien, xiii. 1881, p. 121, pl. iii. fig. 3. 
Parancistrus punctatissimus Kigenm. & Tigenm. Proc. Cal. Ac. (2) ii. 1889, p. 44; Occ. Pap. 
Cal. Ac. i. 1890, p. 423. 
Depth of body about 5 times in the total length, length of head 3 times. Depth of 
head about 1# times in its length, diameter of eye 6 times, interorbital width 3 times. 
Snout rounded anteriorly; supraorbital edges slightly raised; supraoccipital flat, 
without median ridge; temporal plates not carinate; interoperculum armed with 
slender spines, the longest equal to about twice the diameter of eye. Scutes spinulose, 
not carinate, 22 in a longitudinal series, 6 between dorsal and adipose fin, 11 between 
anal and caudal. Supraoccipital bordered posteriorly by a median scute and by one 
on each side. Lower surface of head and abdomen naked. OD. I 7, the first ray equal 
to about + the length of head, the last about 3 as long, and entirely connected by 
membrane to the spine of the adipose fin; length of base of dorsal greater than 
its distance from caudal. A. 14. Pectoral spine extending beyond base of ventral. 
Caudal weakly and obliquely emarginate. Caudal peduncle twice as long as deep. 
Brown, with white or light blue dots on head, body, and fins. 
R. Amazon. 
The above is taken from Steindachner’s description and figure of a specimen 
135 mm. in total length. 
21. ANCISTRUS AURANTIACUS. 
Hypostomus aurantiacus Casteln. Anim. Am. Sud, p, 43, pl. xxi. fig. 2 (1855). 
Hypostomus nigricans Casteln. t. c. p. 44, pl. xxii. fig. 1. 
Hypostomus vicinus Casteln. t. ce. p. 45, pl. xxiii. fig. 1. 
Parancistrus aurantiacus Bleek. Ned. Tijd. Dierk. i. 1863, p. 79. 
Chetostomus aurantiacus Giinth. Cat. Fish. v. p. 246 (1864). 
Chetostomus nigricans Giinth. 1. ec. 
Parancistrus nigricans Eigenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 44. 
Depth of body about 45 times in the total length, length of head 23-24 times. 
“65 =) 
Head broader than long and 14-2 times as long as deep. Diameter of eye 6-8 times 
in the length of head, interorbital width 23-23 times, length of snout 13 times. 
