14 ON SPECIES OF CYNOPOTAMU8. 



rays in the anal vary from 42 to 46. Hab. Rosario, 

 Goyaz, and Sao Paolo. 



CYNOPOTAMUS BISERIALIS sp.n. 



D. 11, A. 47, V. 8, P. 13, L.I. 62, L.tr. -g- 

 Both upper and lower jaws without external toothlike 

 processes ; no canines ; teeth conical, in two series on in- 

 termaxillaries and on the anterior halves of the mandibles ; 

 a single series of maxillary teeth. The two series of teeth 

 on the mandibles serve as a ready means of distinguishing 

 this species from O. gibbosus, and C. pauciradiatus, which 

 it approaches in shape. The back is elevated, decurved 

 toward the occiput, and the depth is one-third of the 

 length to the bottom of the caudal notch. CCbe head is a 

 little more than one-fourth of the length, excluding the 

 caudal. Eye large, two and two-thirds times in length of 

 head, wider than interorbital spdce. The maxillary near- 

 ly or quite reaches a vertical through the centre of the 

 eye. The fourth or fifth ray of the dorsal fin is in the 

 middle of the entire length, without the caudal, and the 

 anterior ray of the dorsal is slightly behind that of the anal. 

 Flanks silvery, humeral and caudal spots present. Many 

 examples were secured by the Thayer Expedition at Lago 

 do Maximo, Obydos and Villa Bella. 



