SOUTH AMERICAN NEMATOGNATHI. 375 



orbital flattish, a shallow groove extending backward 

 from the nares. Margin of snout naked. 



Orbit with a triangular notch on its posterior rim, 

 which is I as long as the orbit; diameter of orbit with- 

 out notch, 3 f in the snout, 8 in the head, If in the 

 iiiterorbital. 



Lower surface of the head naked except a narrow mar- 

 ginal band. 



No teeth in the upper jaw; lower jaw with a few mi- 

 nute teeth. Upper lip rather coarsely fringed, lower lip 

 broad, covered with thick papillae. 



Anal plate joined to the plates preceding it, forming a 

 subtriangular buckler. Nuchal plates inconspicuously 

 bicarinate. Lateral keels remaining separate to the 

 caudal but becoming approximated on the 25th lateral 

 scute. Tail with a median depression above and below. 



Distance of dorsal fin from tip of snout 2| in the 

 length; first dorsal ray highest, 1-f in the head. Caudal 

 emarginate, upper lobe a little the longer. Anal rounded, 

 lower than the ventrals. Third ventral ray highest, 

 reaching slightly beyond origin of anal; pectoral reach- 

 ing to base of ventral. 



Color uniform dark brown. 



Head 3J-3-J; D- 8; A. 6; V. I, 5; P. I, 6. 



Two specimens .28-. 33 m. Rio Grande do Sul. Dom 

 Pedro II. 



317, Loricaria acuta, 



Loricaria acuta Cuv. & Val. Hist. Nat. Poiss, xv, 472 (? Brazil); 

 Kner, Panzer\velse, 85, 1853 (Barra do Kio Negro); Giiiither, v, 

 258, 1864 (copied); Vaillaiit, Bull. Soc. Philom. Ser. 7, iv, 159, 

 1880 (Calderou); Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. ii, 

 38, 1889 (Villa Bella; Lake Hyaimary; Cudajas; Mauaos, on the 

 Rio Negro; Xiugu Cascade; Lago Alexo; Obidos; Coary; Teffe.) 



? Loricaria castanea Castelnau, Anim. Amerique du Sud, 46, plate 

 xxiii, fig. 4, 1855 (Rio de Janeiro.) 



/ Loricaria macalata Giinther, Catal. v, 257, 1864 (British Guiana; 

 Surinam). 



Habitat; Amazons and northward. 



