230 MR. C. TATE REGAN ON THE 
dorsal and adipose fin, 13 between anal and caudal. Supraoccipital entirely bordered 
posteriorly by a single scute. Lower surface of head and abdomen, in the adult, to a 
considerable extent covered with small granular scales. D. I 7, the first ray $-# the 
length of head, the last 3-3 as long; length of base of dorsal little less than its distance 
from the caudal. A. I 4. Pectoral spine extending nearly to middle of ventral. 
Caudal obliquely emarginate or truncate. Caudal peduncle 2$-3 times as long as 
deep. Rather large round dark spots on head, body, and fins. 
Total length 220 mm. 
‘lwo specimens: Surinam. 
9. ANCISTRUS GIGAS. 
? Chetostomus aculeatus Perugia, Ann. Mus. Genov. (2) x. 1891, p. 637. 
Chetostomus gigas Bouleng. Proc. Zool. Soc. 1895, p. 526, and Trans. Zool. Soc. xiv. 1896, p. 30, 
pl. vi. 
Depth of body 4} times in the total length, length of head 2} times. Head 1} times 
as long as broad and 14 times as long as deep. Diameter of eye 13 times in the 
length of head, interorbital width 2+ times, length of snout 12 times. Length of 
mandibular ramus 33 times in the interorbital width. Snout broad, rounded ; 
supraorbital edges not raised; occipital and interorbital regions flat ; interoperculum 
armed with very numerous rather slender spines with curved tips, the longest equal to 
‘the length of head. Scutes strongly spinulose, all carinate, 25 in a longitudinal 
series, 5 between dorsal and adipose fin, 1l between anal and caudal. Supraoccipital 
bordered posteriorly by a single scute. Lower surface completely covered with small 
granular scales. D. 110; length of base of dorsal 1} times its distance from caudal. 
A.15. Pectoral spine extending to middle of ventral. Caudal truncate. Caudal 
peduncle twice as long as deep. Rather large dark spots on head, body, and fins. 
Total length 550 mm. 
One specimen: Asuncion, Paraguay. 
10. ANCISTRUS ASPIDOLEPIS. 
Chatostomus aspidolepis Giinth. Proc. Zool. Soc. 1866, p. 603; Trans. Zool. Soc. vi. 1866, p. 477. 
Hemiancistrus espidolepis Eigenm. & Higenm. Proc. Cal. Ac. (2) ii. 1889, p. 43. 
Depth of body 5} times in the total length, length of head 3 times. Head 1} times 
as long as broad and twice as long as deep. Diameter of eye about 8 times in the 
length of head, interorbital width 23 times, length of snout 1} times. Length of 
mandibular ramus 1? times in the interorbital width. Snout broad, rounded; supra- 
orbital edges slightly raised ; supraoccipital convex, without distinct ridge; temporal 
plates carinate ; interoperculum armed with a few short spines. Scutes spinulose, 
strongly carinate, 25 in a longitudinal series, 7 between dorsal and adipose fin, 12 
between anal and caudal. Supraoccipital bordered posteriorly by a single scute. 
