516 PROCEEDINGS OF THE ACADEMY OF [Jl^^ty, 



less extent which is entirely free from pigment, and behind by two yel- 

 lowish spots. Three specimens (part of 253) are light straw color 

 with a yellowish fatty hnmeral area ; a faint dark line along the middle 

 of the sides. In two of these the spines of the lower caudal are nearly 

 typical, in the third they are weak. Arroyo Trementina. 



Seven specimens (part of 219) are notably darker; in only one of 

 these is the serration of the caudal spines typical. Young with a 

 black lateral band. AiToyo Pypucii. 



Nine specimens (257), slender, elongate, quite dark, three of them 

 with the typical caudal serrature, the others with the caudal rays not 

 spine-like. Ai-royo Pypucu. 

 60- Aphyocarax dentatus sp. nov. Piki. 



Type No. 10,030 (part of No. 6), 71 mm. Asuncion, Rio Paraguay 

 (Laguna). November, 1899. 



Co-types, four specimens. No. 10,038 (part of No. 6), 53-71 imn. 

 Asuncion. One specimen. No. 10,033 (96), 70 mm. Asuncion. April, 

 1900. Six specimens. No. 10,030 and 10,031 (237 and 247), 33-60 mm. 

 From Aguadas, near Arroyo Trementina. December, 1900. Four 

 specimens. No. 10,036 (8), 65-80 mm. Asuncion, Rio Paraguay (La- 

 guna). November 1899. Piki. One specimen. No. 10,037 (found 

 with 90). From Asuncion, Rio Paraguay. April, 1900. Taken with 

 a seine. 



This species differs from pusillus and alburnus chiefly in the length of 

 the snout and the maxillary and in the numl3er of teeth in the man- 

 dible. 



Elongate, ventral profile slightly more curved than the dorsal. 

 Dorsal profile but slightly convex from the tip of the snout to the ori- 

 gin of the dorsal, from origin of dorsal to base of caudal straight. 



Head small, 4 in length, its depth If in its length. The teeth in a 

 single series above and below. Maxillary teeth largely concealed, 

 covering over half the anterior edge in the young; less in the old on 

 account of the great elongation of the maxillary. Maxillary short in 

 young, increasing rapidly in length with age, scarcely reaching 

 beyond origin of eye in yomig, to end of pupil in the old. 



Mouth small, very oblique in young, large and horizontal in adiilt,the 

 jaws equal. Second and third suborbital bones large, entirely covering 

 the cheek. The opercle triangular, its width li in its depth. 



The eye small, 1 in snout, 4 in the head, U in the interorbital. 



The dorsal small, its height li in the length of the head. Its last 

 ray 2^ in its height. Depth of caudal peduncle little less than half the 

 length of the head. 



