448 CALIFORNIA ACADEMY OF SCIENCES. 



dark spot on the base of the membrane between the dor- 

 sal spine and the first ray. 



Head 2-2f ; D. I, 7; A. 5; Lat. 1. 24. 



Thirteen specimens .07-. 21 m. Coary; Tabatinga; 

 Jutahy. Thayer expedition. 



440, Ancistrus hoplogenys, 



Chcetostomus hoplogenys Giinther, v, 247, 1864 (Kiver Capin, Para). 

 Ancistrus hoplogenys Eigenm. & Eigenm. Proc. Cal. Aoad. 2d. Ser. 



ii, 48, 1889 (Tajapuru). 

 Two specimens .06-. 13 m. Tajapuru. L. Agassiz. 



441, Ancistrus temminkii. 



< Hypostomus temminkii Cuv. & Val. Hist. Nat. Poiss. xv, 514, 1840 



(Cayenne). 

 Ancistrus temminkii Bleeker, Silures de Surinam e, 11, pi. i, fig. 3 and 



pi. ii, fig 2, 1864 (Surinam); Eigenm. & Eigenm. . 1. c. (Cudajas; 



Gurupa; Lake Hyanuary; Teffe; lea; Kio Trombetas; Jutahy; 



Serpa; Kio Madeira; Ueranduba; Tabatinga). 

 Ancistrus dolichopterus Kner, Hypostomiden, 274, pi. iii, fig. 1, 1853 



(Barra do Kio Negro). 

 Chcetostomus dolichopterus Giinther, v, 249, 1864 (copied); Vaillant, 



Bull. Soc. Philom. series 7, iv, 155, 1880 (Calderon). 

 Habitat: Surinam; Amazons from Gurupa westward. 



Closely related to Chcetostomus leucostictus Giinther, 

 from which it differs in the following characters: 



Median tentacles of the male more numerous and with 

 broader bases. Preopercular spines fewer. 



Base of the dorsal equals its distance from the middle 

 caudal rays. Caudal obliquely truncate, the outer rays 

 not produced, the lower lobe longer. 



Dark brown with indistinct darker spots; dorsal and 

 caudal uniform dusky, or sometimes with dark spots 

 smaller than those on the body; a dark spot on the base 

 of the membrane between the dorsal spine and the first 

 ray; pectoral and ventral fins dotted with light. 



Head 2|-3; D. I, 8-9 (7 in one specimen); A. 5; Lat. 

 1. 24. 



Over fifty specimens from .06-. 20 m. Cudajas; Guru- 

 pa; Lake Hyanuary; Teffe; Iga; Jutahy; Serpa; Rio Ma- 

 deira; Ueranduba; Tabatinga; Rio Trombetas. 



