Fisher: Hypophthalmid^, Diplomystid^, Silurid^. 427 



D. 1.6; A. 34-37; V. 8; Head 3.25; depth at origin of dorsal 4.75; 

 width below origin of dorsal 5; snout two and one-quarter times in 

 head, one in interorbital. 



Body elongate, compressed toward the caudal. Head depressed, 

 covered with skin, snout spatulate, the upper jaw produced one-half 

 the length of the eye. Fontanel narrow, continued as a groove to the 

 base of the occipital process, which is extended to meet the dorsal 

 plate. Rones of the head somewhat striated. 



Eye strictly lateral, its margin not free, three times in the snout, 

 about eight times in the head, and three times in the interorbital. 



Teeth as in Ageneiosus ucayalensis, but the band narrower, the 

 depth of the band less than half the diameter of the eye. 



Dorsal high, its height equal to three or more times the length of its 

 base. Dorsal spine pungent, toothed on its anterior margin, its 

 posterior margin smooth. First soft ray of the dorsal as long as, or a 

 little longer than, the spine; the last ray less than one-third the length 

 of the spine; the spine strong, somewhat shorter in the female than in 

 the male. The origin of the dorsal from the snout 

 two and two-fifth times in the length of the fish. 



Pectoral spine strong, with moderately recurved 

 teeth on its posterior margin, its dorsal margin 

 slightly roughened; dorsal and ventral surfaces of the 

 spine distinctly striate. The spine sharp; five to five 

 and four-fifths times in the length of the fish. Pec- 

 torals not quite reaching the ventrals; the ventrals 

 reaching one-fourth their length past the origin of 

 the anal. 



Adipose short, its base equal to the diameter of the 

 eye or shorter; caudal forked. Back marbled with 

 irregular, dark purple spots and blotches, the largest 

 of which are almost equal to the length of the diam- 

 eter of the pupil of the eye. Dorsal, pectorals, and 

 caudals with a few small purplish spots near their 

 bases. The ventrals and anals plain. 



This species is closely related to Ageneiosus 

 valenciennesi Bleeker, from which it dififers by the 

 longer pectoral spine, the longer head, and the much weaker den- 

 tition. 



Fig. 5. A. ma- 

 deirensis Fisher. 

 Right pectoral 

 spine. X 3- 



