SOUTH AMERICAN NEMATOGNATHI. 149 



XXVIII. Paradiplomystes Bleeker. 

 Paradiplomystax Giintlier. 



135. Paradiplomystes coruscans (Lichteusteiu). 



XXIX. DiPLOMYSTES Bleeker. 

 Diplomystax Giinther. 



136. Diplomystes papillosus (Cuv. & Val.) 



?? Silurus chilensix Liumcus; Arius carchar'ias Leyboldt; A.vllloms, 

 squalus, micropierus aud syuodon Plnlippi. 

 Locality: Rivers of Santiago. 



XXX. Ageneiosus Lacepede. 



Ger atorhy nchus AgRSsiz; Hypothalmus Scliomburgk ; Pseu- 

 dogeneiosus & Davalla Bleeker; Ageniosus Giintlier. 



137. Ageneiosus inermis (Bloch). 



§ Ageneiosus. 



138. Ageneiosus brevis Steindachner. 



Locality : Coary. 



139. Ageneiosus atronasus sp. nov. 



Oue specimen; length .095 m. Exact locality unknown. 



Bod}^ as broad as deep under the dorsal spine. Head 

 short, depressed, not much elevated behind the e^-es, the 

 profile nearly straight, much less steep than in hrevis, the 

 head covered with thin skin, the surface of the bones longi- 

 tudinally ridged; greatest width of the head 1^ in its 

 length, width at rictus 1.^; snout as in brevis, broadly 

 rounded in front. Fontanel short, ending over center of 

 eye, but continuing as a groove backward to the posterior 

 margin of the eye. Occipital process scarcely as long as 

 its basal \\ idth, coossified with the dorsal plate, its surface 

 ridges somewhat granular. 



Eye 1 in snout, 3j in head, 2 in the interocular. 



Maxillary barbel bony at base, the bony portion being 

 two-thirds of the whole length of the barbel, extending be- 

 yond the rictus half the total length of the barbel, its lower 

 edge veryminutely crenulate near its tip. 



