EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 231 



97. Hemiancistrus schomburgki Gunther. 

 Chcetostomus schomburgkii Gunther, Catalogue, V, 1864, 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 Gunther. 



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 Siidamerika's," ii, 1881, 24, pi. 5, 

 fig. 3. 

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



No. 11958.) 



