336 Annals of the Carnegie Museum. 



No. 2577, cotype, 13 cm., Sao AnLonio dc Guapore, Rio Guapore, 

 July 23, 1909. 



D. X\', 10; A. 111,8; "^ "'- ; scales 3.5-24 to 26-9; depth almost 

 8-9 



2; maxillaries not extending to the anterior margins of the eyes; 

 diameter of eye 3.5 in head, almost 2 in the interorbital space, and 

 equal to the preorbital width; snout one-half as long as the head, 

 and distinctly longer than the postorbital j:)ortion of the head; pre- 

 operculum scaleless; four rows of scales on the cheeks; caudal 

 peduncle two-thirds as long as deep; one and a half scales between the 

 lateral line and the first dorsal rays; six gill-rakers on the lower ante- 

 rior arch; pectoral fin one and a third times the length of the head; 

 caudal scaled almost to its tip, but other fins scaleless; dorsal spines 

 increasing until the last, which is more than one-half the length of the 

 head; caudal round; a faint lateral band and seven cross-bars with a 

 large dark spot on the third one; a dark spot on the upper edge of the 

 base of caudal; fins dusky but spotless; no spot or bar beneath the 

 eyes; fold of the lower lip not continuous. This species has a broader 

 interorbital, longer dorsal spines, longer pectoral fins, thicker body, 

 fewer scales between the lateral line and first dorsal rays, different 

 coloration, and a greater depth than the same-sized A. tetramerus, 

 its nearest ally. 



I have dedicated this species to Awan, a Pawumwa Indian, who 

 made his first acquaintance with a white man when aiding me with 

 a seine in the Guapore river. His name is the name of the vine 

 from which they make the poison for their arrows. 

 19. A. dorsigera (Meckel). 



A. Jrenijera Cope, A. flavilabrus Cope, A. thayeri (Steindachner). 

 No. 2564a-&, 2 and 3.5 cm., Corumba, Rio Paraguay, April 27, 1909. 

 No. 25650-/, 2.5 to 3.3 cm., Puerto Suarez, Bolivia, May 7, 1909. 

 No. 2566fl-c, 2.4 cm., Sao Luiz de Caceres, Rio Paraguay, May 24, 



1909. 

 No. 2567, 2.5 cm., San Joaquin, Bolivia, Sept. 4, 1909. 

 No. 2568, 2.5 cm., Rio Alegre, Aug. 3, 1909. 



A. Ill, 7. 

 No. 2569, 3.5 cm., Sao Antonio de Guapore, Rio Guapore, Aug. 3, 1909. 



Eye 3 in the head; a spot on the sides of the body below the sixth 

 to tenth scale of the lateral line; twenty-two scales in a series below the 

 lateral line; D. XV, 8; A. Ill, 8. 



