276 PROCEEDINGS OF THE ACADEMY OF [Apr., 



Gill-opening small, restricted, lateral, extends forward about 

 opposite first | in eye and extends behind latter nearly half an 

 eye-diameter. 



Scales, or scutes, all minutely spineseent. Predorsal region with 

 4 scutes- to occipital. Five series of scutes transversely across 

 belly, each outer series of larger ones. A single scute interposes 

 each side medianly between anal plate and preanal plate. 



Dorsal origin about first third in space between snout tip and 

 caudal base, spine ends in filament extending back slightly less than 

 half way to caudal base. Anal inserted well behind dorsal base or 

 about midway between snout tip and thirty-second lateral scute, 

 flexible spine, reaches 3f to caudal base. Caudal small, upper and 

 lower, or outer, rays produced in filaments, latter at least f rest of 

 body length, and fin deeply forked. Pectoral with flexible spine 

 extends slightly beyond ventral origin. Ventral inserted opposite 

 dorsal origin, spine flexible, extends back slightly beyond anal origin. 

 Vent midway in space between ventral and anal origins. 



Color in alcohol brownish above, with dark lateral streak or ill- 

 defined band extending along each side of snout from tip, including 

 eye, embracing region of obsolete upper and distinct median lateral 

 keels and then continued externally along edge of caudal peduncle 

 where, however, narrow. Lower surface of snout dusky. Entire 

 lower surface of head and body otherwise pale brownish to whitish. 

 Fins all pale, dorsal obscurely mottled or blotched with pale dusky. 

 Caudal with edges above and below, and filaments pale, median 

 rays whitish, and posterior inner portions of both lobes more or less 

 mottled dusky, that of lower nearly blackish and mostly uniform. 

 Iris slaty. 



Length 265 mm. 



Type, No. 39,346, A. N. S. P. Rupununi River, British Guiana. 

 J. Ogilvie. 



This species is closely related to Sturisoma rostrata (Spix) and, 

 as compared with the specimen Cope recorded from the Peruvian 

 Amazon as Loricaria rostrata,-^ differs in the coloration. Cope's 

 example also shows the fins less produced and two plates each side 

 imposing between plate containing vent and preanal. 



(i)Ji'ry()<^^ one; tt^/'ttj, shield; with reference to the single interposed 

 shield between ventral and anal plate.) 



='Prof. Amer. Philos. Soc, Phila., XVII, 1878, p. 681. 



