eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 239 



48; Occasional Papers Cal. Acad. Sci., I, 1890, 446 (Cudajas; Obidos); Proc. 



U. S. Nat. Mus., XIV, 1891, 43.— Eigenmann, Repts. Princeton Univ. Exp. 



Patagonia, III, 1910, 411. 

 Chcetostomus cirrhosus Gunther, Catalogue, V, 1864, 247 (Essequibo, British 



Guiana). — Hensel, Archiv fur Xaturg., I, 1870, 76 (stony mountain streams). 

 -Vaillant, Bull. Soc. Philom., (7), IV, 1880, 155 (Calderon).— Steix- 



dachner, " Flussfische Siidamerika's," iv, 1882, 7 (Rio Huallaga). — Perugia, 



Ann. .Mus. Genova, (2). XVIII, 1897, 21 (Rio Beni). 

 Xrnocara cirrhosa Regan, Trans. Zool. Soc. London, XVII, 1904, 256 (Rio Para- 

 guay; Amazon; Guiana; Trinidad). 

 Chcetostomus variolus Cope, Proc. Acad. Xat. Sci. Phila., 1871, 288 ( Ambyiacu).— 



Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 1889, 64; Occa- 

 sional Papers Cal. Acad. Sci., I, 1890, 442. 



Three specimens, 48 to about 100 mm. Ireng River near Holmia. (C. M. 

 Cat. Xo. 1523; I. U. Cat. No. 11949.) 



Head 2.85-3; depth at tip of occipital 2.4 in the head; width of head an orbital 

 diameter less than its length; interorbital 2.4 in the head; mandibular ramus 2-3 

 in the interorbital; D. 1,7; A. 1,4; eye 5.5 in the head in the largest specimen; 

 about twelve interopercular spines, the longest 4.5 in the head. 



Tentacles numerous, the naked area reaching half-way to the posterior margin 

 of the eye in the largest specimen, which is a male; six plates between the dorsals, 

 ten between the anal and caudal, and twenty-four along the sides. 



Last dorsal ray scarcely reaching the spine of the adipose; base of dorsal a 

 little greater than its distance from the adipose; dorsal spine equal to snout and 

 eye; ventrals about reaching middle of anal; pectoral spine reaching third fifth 

 of ventrals. 



Black, with faint white spots; dorsal and caudal with dark spots along the 

 rays; pectorals and ventrals spotted or plain. 



106. Ancistrus hoplogenys (Gunther). 

 Chcetostomus hoplogenys Gunther, Catalogue, V, 1864, 247 (River Capin, Para). 

 Ancistrus hoplogenys Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 



1889, 48; Occasional Papers Cal. Acad. Sci., I, 1890, 448 (Tajapuru); Proc. 



U. S. Xat. Mus., XIV. 1891, 43.— Eigenmann, Repts. Princeton Univ. Exp. 



Patagonia, III, 1910, 411. 

 Xenocam hoplogenys Regan, Trans. Zool. Soc. London, XVII, 1904, 255 (Guiana; 



Amazon; Rio Paraguay ). 



