230 ME. C. TATE BEGAN 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 f-f the 

 length of head, the last f-f 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 2f-3 times as long as 

 deep. Rather large round dark spots on head, body, and fins. 



Total length 220 mm. 



Two specimens : Surinam. 



9. Ancisteus gigas. 



? Chcetostomus aculeatus Perugia, Ann. Mns. Genov. (2) x. 1891, p. 637. 



Chatostomus gigas Bouleng. Proc. Zool. Soc. 1895, p. 526, and Trans. Zool. Soc. xiv. 1896, p. 30, 

 pi. vi. 



Depth of body 4^ times in the total length, length of head 2-^- times. Head 11 times 

 as long as broad and If times as long as deep. Diameter of eye 13 times in the 

 length of head, interorbital width 2-j times, length of snout If times. Length of 

 mandibular ramus 3§ times in the interorbital width. Snout broad, rounded ; 

 supraorbital edges not raised ; occipital and interorbital regions fiat ; 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, 1 1 between anal and caudal. Supraoccipital 

 bordered posteriorly by a single scute. Lower surface completely covered with small 

 granular scales. D. I 10 ; length of base of dorsal 1^ times its distance from caudal. 

 A. I 5. 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 530 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 aspidolepis Eigenm. & Eigenm. 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 2f times, length of snout If times. Length of 

 mandibular ramus If 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. 



