eigenmann: the freshwater fishes of British guiana 231 



97. Hemiancistrus schomburgki ( Hinther. 

 Chcetostomus schomburgkii Gtjnther, Catalogue, V, 1804, 245 (British Guiana). 

 Hemiancistrus schomburgkii Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 



II, 1889, 43; Occasional Papers Cal. Acad. Sci., I, 1890, 420. — Kindle, Ann. 



N. Y. Acad. Sci., VIII, 1895, 254. 

 Ancistrus schomburgkii Regan, Trans. Zool. Soc. London, XVII, 1904, 233 (Guiana). 

 —Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 408. 



No specimens were secured. 



"Depth of body 8 times in the total length, length of head 3 times. Head 

 nearly as broad as long and 2f times as long as deep. Diameter of eye 4f-5f 

 times in the length of head, interorbital width 2f times, length of snout 1^ times. 

 Length of mandibular ramus 2^ times in the interorbital width. Snout broad, 

 rounded; supraorbital edges not raised; supraoccipital flat, without median ridge; 

 temporal plates not carinate; interoperculum armed with 20-25 slender spines with 

 curved tips, the longest equal to twice the diameter of eye. Scutes spinulose, not 

 carinate, 25 in a longitudinal series, 6 between dorsal and adipose fin, 11-12 be- 

 tween anal and caudal. Supraoccipital bordered posteriorly by a median scute 

 and by one on each side. Lower surface of head and abdomen naked (in the young) . 

 D. 1,7, the first ray f the length of head; length of base of dorsal nearly equal to 

 its distance from the adipose fin. A. 1,4. Pectoral spine not reaching the base 

 of ventral. Caudal peduncle 3 times as long as deep. Brownish, clouded with 

 darker; dark spots on the fins. 



"Total length 75 mm." — Regan. 



98. Hemiancistrus megacephalus Giinther. 



Chcetostomus megacephalus Gunther, Proc. Zool. Soc. London, 1868, 232 (Suri- 

 nam ?). 



Hemiancistrus megacephalus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., 

 (2), II, 1889, 44; Occasional Papers Cal. Acad. Sci., I, 1890, 420; Proc. U. S. 

 Nat. Mus., XIV, 1891, 41.— Kindle, Ann. N. Y. Acad. Sci., VIII, 1895, 253.- 

 Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 408. 



Ancistrus megacephalus Regan, Trans. Zool. Soc. London, XVII, 1904, 234 

 (Guiana). 



Chcetostomus macrops Lutken, Vid. Med. Naturhist. For. Kjobenhavn, 1874, 209 

 (Surinam). — Steindachner, " Flussfische Sudamerika's," ii, 1881, 24, pi. 5, 



fig. 3. 



Nine specimens, 86-185 mm. Amatuk. (C. M. Cat. No. 1536^-6; I. U. Cat. 

 No. 11958.) 



