eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 253 



eye equidistant from tip of snout and anus; snout in front of the naked area about 

 the mouth 3 in the distance to the anus; postorbital part of the head 3.5 in the 

 snout. Distance from supraoccipital to the dorsal 6 in the length; snout long, 

 slender, granular, expanded at the tip.' 



Seven plates between the supraoccipital and the dorsal; lateral plates thirty- 

 three (14 + 19). 



Much faded, but outer margins of caudal evidently dark. 



Named for Mr. T. Sydney Hargreaves, author of "The Fishes of Guiana," 

 who presented the specimen to the Museum of Georgetown. 



Order HETEROGNATHI. 

 Family CHARACID^. 

 = Characini Muller, Archiv fur Naturg., IX, i, 1843, 323. 

 = Characinida; Richardson, Encycl. Brit., ed. 8, XII, 1856, 245. 

 > Characidce Gill, Mem. Nat. Acad. Sci., VI, 1893, 131. 



This large family includes fishes of nearly all shapes and sizes, and inhabiting 

 all sorts of fresh-waters in tropical South America. The species found in Guiana 

 are distinguished from the other fishes of that country by the presence of scales, a 

 short dorsal fin without spines, and a short adipose dorsal fin. The latter, however, 

 is absent in Hoplias, Erythrinus, Carnegiella, Pcecilocharaz, and Nannostomus. 



Key to the Guiana Geneea of Characim:. 

 a. Mouth protractile; no teeth; gills with forward-directed lamella'. An adipose fin; upper jaw rudimentary, 



lower jaw large, well-developed. (Bivibranchiina.) Bivibranchia. 



aa. Mouth not protractile. 



b. Teeth none; an adipose fin; lower jaw firm, with a thin edge; intestine very long; gill-rakers none or 

 modified. ( Curimatinw.) 

 c. Lateral line incomplete; caudal naked; tongue long, narrow; mouth very oblique, c3q)rinodontiform. 



Curimatopsis. 

 cc. Ventral surface not spiniferous; lateral line complete; tongue broad, adnate; mouth terminal or 

 inferior. 



d. Caudal lobes densely scaled Curimatella. 



dd. Caudal lobes naked Curimatus. 



(ccc. Post-ventral surface trenchant, spiniferous; predorsal area scaled Psectrogaster.) 



bb. Teeth minute on the margins of fleshy lips, movable; gill-membranes joined to the isthmus. (Cf. bbb.) 



e. Gills normal; mouth large, evertible to form a circular sucking disk; teeth numerous on both lips, 



in single series on the sides, in two in the middle; a predorsal spine; scales rough; species 



of large size. (ProchilodiruB.) Prochilodus. 



ee. Fourth gill-arch dilated behind, its surface with corrugations which fit into similar ones on the con- 

 cave fifth arch; mouth small; no predorsal spine; species small. (Chilodinae.) 

 f. Anal emarginate, the highest rays extending beyond the tip of the last; scales with serrate 

 margins; feeble teeth in both jaws, those of the upper jaw bifid Tylobronchus. 



