SOUTH AMERICAN NEMATOGNATHI. 369 



occipital with two ridges which widen backward and are 

 continued upon the nuchal plates; two nuchal plates 

 between the occipital and the dorsal plate with a deep 

 median depression; occipital truncate behind, margined 

 by three plates; superciliary margins raised, the inter- 

 orbital concave. 



Orbit with a rather large notch behind; eye 4 in the 

 snout, 7h in the head, 1^- in the interorbital. 



Anterior profile convex. Teeth few, well developed 

 in both jaws. Margin of the lips fringed, short cirri 

 covering the surface of the lips. Free portion of the 

 barbel about equal to the orbital diameter. 



Lower surface of the head naked; belly with 3-5 series 

 of scutes; anal plate narrowest forward, emarginate be- 

 hind. 



Lateral keels coalescing on about the 16tli lateral 

 scute. Anterior canals and pores of the lateral line dark 

 purplish. Pectoral pore minute. 



Distance of the dorsal fin from tip of snout 3^ in the 

 length; dorsal fin about ^-h higher than long. 



Caudal slightly emarginate, the upper ray produced, 

 2;V in the length. Ventrals short, not reaching to the 

 anal; pectorals about to the ventrals. 



Back marbled, and with traces of about 4 dark cross 

 bars; mucous pores of the head and anterior portion of 

 the body dark purple; all the fins^spotted, the anal least; 

 base of caudal dusky; tips of caudal and dorsal sometimes 

 blackish, the anal sometimes with a dusky bar. 



Head 4|; D. 8; A. 6; V. I, 5; P. I, 6; Lat. 1. 27-28. 



Twenty-eight specimens, .10-. 17 m. to base of caudal. 

 Mendez; Santa Cruz; Rio Quenda; Rio Parahyba; Cam- 

 pos; Macacos. 

 21 



