SOUTH AMERICAN NEMATOGNATIII. 375 



orbital fiattish, a shallow groove extending backward 

 from the nares. Margin of snout naked. 



Orbit with a triangular notch on its posterior rim, 

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

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

 interorbital. 



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. Upj)er lip rather coarsely fringed, lower lip 

 broad, covered with thick papilla3. 



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 2f in the 

 length; first dorsal ray highest, 1| 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 3A-3-|; D- 8; A. 6; V. I, 5; P. 1, 6. 



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

 Pedro II. 



317. Loricaria acuta. 



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

 Kuer, Panzerwelse, 85, 185.3 (Barra do Eio Negro); GUuther, v, 

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

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

 38, 1889 (Villa Bella; Lake Hyauuary; Ciidajas; Mauaos, ou the 

 Kio Negro; Xingii Cascade; Lago Alexo; Obidos; Coary; Teffe.) 



? Loricaria castanca Castelnan, Anim. Amerique du Sud, 46, jilate 

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



? Loricaria inacalata Giiuther, Catal. v, 257, 1864 (British Guiana; 

 Surinam). 



Habitat; Amazons and northward. 



