SOUTH AMERICAN NEMATOGNATHI. 301 



flexible, rugose in front. Dorsal surface irregularly marbled 

 with brownish purple; an occellus above gill-opening. Head 

 3f ; A. 44. porphyreus 343. 



ff. Head 3 in the length, a third longer than broad; snout parabolic, 

 the upper jaw longer. Maxillary barbel filiform, extending be- 

 yond anterior margin of the eye; gape of the mouth more than 

 half the length of the head; eye 6 in head, less than 4 in interoc- 

 ular; spines smooth, slender, half as long as the fins. Grayish, 

 with large spots. Br. 11; D. I, 6; A. 38. dawalla 244. 



aa. Caudal obliquely truncate. (PSEUDAGENEIOSUS). 



j. Pectoral pore a small round opening; eye rather small, its diameter 

 less than half its distance from posterior nostril. brevifilis 245. 



jj. Pectoral pore wider than the anterior nostril and closed by a mem- 

 brane perforated by many smaller foramina. Eye rather large, its di- 

 ameter being two-thirds of its distance from posterior nostril. Width 

 of head 1 in its length; snout very obtuse. Anterior margin of eye 

 nearer end of snout than to edge of opercle. Maxillary barbel not reach- 

 ing the rictus. Dorsal spine less than half as long as the head. Sides 

 with whitish bands; dorsal fin and upper side of pectoral with brown 

 spots; basal half of caudal black. Head 3|; D. I, 6; A. 38; V. 8. (Giin- 

 ther.) axillaris 246. 



236. Ageneiosus brevis. 



Ageniosus brevis Steindachner, Flussfische, Sudani, iii, 16, 1881 



(Amazon.) 

 Ageneiosus brevis Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. i. 



149, 1888 (Coary.) 

 Habitat: Solimoens. 



Body short and deep, the depth everywhere greater 

 than the width. Head short, depressed anteriorly, ris- 

 ing rapidly behind the eyes, the profile steep, concave; 

 the head covered with skin, the surface of the bones lon- 

 gitudinally ridged; the greatest width of the head 1| in 

 its length, the width at rictus If; the snout broadly 

 rounded in front. Fontanel short, not extending to pos- 

 terior margin of eyes. Occipital process wider at base 

 than its length, coossified with the dorsal plate. 



Eye 1 in snout, 3J in head, 2 in interocular space. 



Maxillary barbel simple, minute, without perceptible 

 bony base. Snout short, one-half interocular width. 

 Cleft of mouth about 5 in the length of the head; upper 



