SOUTH AMERICAN NEMATOGNATHI. 151 



147. Ageneiosus axillaris GUntber. 



XXXI. Tetranematichthys Bleeker. 



148. Tetranematichthys quadrifilis (Kner.) 



XXXII. AUCHENIPTERUS Cuv. & Val. 

 Euanemus Miiller & Troschel. 



149. Auchenipterus nuchalis (Spix.) 



Auchenipterus dentatus Cuv. & Val.; Euanemus colymbetes Miiller & 



Troschel. 

 Locality: Villa Bella. ? 



150. Auchenipterus fordicei sp. no v. 



Type, No. 7289, oue specimen, length .12 m. Coary. L. .Igassiz. 



Body short, deep, compressed. Head short; its width 

 equals the distance from tip of snout to middle of opercle; 

 its depth at base of occipital process is little less than its 

 width; top of the head covered with very thiu skin, the sur- 

 face of the bones striate. Occipital process twice as broad 

 as long, parabolic behind, joining the dorsal plate: dorsal 

 plate deeply emarginate in front and behind, less so on 

 sides, its length on a median line 2| in the diameter of the 

 eye. 



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



Maxillary barbel reaching beyond base of ventrals, its 

 osseous base not extending to center of eye; mental barbels 

 reaching to the middle of the ventrals; post-mentals not to 

 the middle of the pectorals. Snout rounded in front; jaws 

 about equal, the width of the mouth at the rictus I5 in the 

 width of the snout at the same place. Teeth as in B. 

 nuchalis. 



Distance of dorsal fin from tip of snout 3^ in the length; 

 dorsal spine 1^ in head, slender, its anterior margin sinootii, 

 its posterior margin with short teeth, the tip of the spine, 

 when depressed, reaching the vertical from the end of the 

 first third of the ventral fins. 



2d See. Vol. I. (11) Issued July 18, 1888. 



