144 THE CYPRINODONTS. 



symphyses firm. Teeth subconical, in bands, outer series larger. Base of 

 dorsal not quite as long as that of anal, originating midway from opercle to 

 base of caudal, above the fourth anal ray. These positions vary with indivi- 

 dual or sex. Pectoral medium, fin reaching behind origin of anal. Ventrals 

 small, close to anal. Caudal rounded, its length about five eighths of that 

 of head. The longest I'ays of dorsal and anal appear at the beginning of 

 the hindmost third or fourth of the fin, from these they decrease to less than 

 half as long at the ends. 



Dull reddish brown, belly yellowish white. Dorsal and anal grayish 

 toward outer margins. La Plata specimens are yellowish brown with a num- 

 ber of not well defined dingy bands across the flanks. Attains a length of 

 four inches or more. Pernambuco to La Plata River. 



Cynolebias Bellottii. 



CynoleUas Bellottii Steiud., 1881, Denk. Ak. Wien, XLIV, extr., p. 9, pi. 5, fig. 3 ; Perug., 1891, 

 Ann. Mus. Civ. Gen., (2) X, 651; Eig., 1891, P. U. S. Mus., XIV, 64, 



D. 23 ; A. 28-29 ; V. 5 ; LI. 30 ; Ltr. ca. 14. 



Body compressed, greatest depth three eighths, and length of head two 

 sevenths times in the length of the body. Diameter of eye three and three 

 fifths times, and width of forehead little more than twice in the length of 

 the head. Crown slightly arched; back more curved from head to dorsal. 

 Mouth broad, nearly horizontal ; jaws firm, lower prominent, massive, upper 

 somewhat protractile. Teeth small, in bands, outer series larger, in open 

 order. Anterior nostrils tubular. Snout short, blunt, subtruncate. Head 

 covered with scales, except on snout and chin to throat. Origin of dorsal 

 little nearer to the snout than to the bases of the median caudal rays, a little 

 behind the origin of the anal ; dorsal rays increasing in height to the thir- 

 teenth, which is nearly two thirds of the length of the head. Anal reaching 

 its greatest depth in the eighth or ninth rays, which are about two thirds of 

 the length of the head. Pectorals well developed, rounded, one third longer 

 than the head, reaching the origin of the anal. Ventrals near the anal, 

 one third of the length of the pectoral. Caudal as long as the pectoral, 

 rounded. 



Head and body dull brownish ; caudal, anal, dorsal, and ventral olivaceous. 

 Pectorals dull brownish gray, lower edge lighter. A dark band from the 

 back of the head obliquely forward and downward through the eye. 



La Plata. 



