[1870. 



563 



Cope. 



Color silvery, anal fin dark edged ; a brighter band on caiidal peduncle, 

 darker edged above. An indistinct postscapular spot. Total length 

 .095 M. The color of the irides in the type specimen, which has not been 

 very long in alcohol, is a dark red. 



There is a spine directed forwards from the base of the first dorsal ray, 

 along the back, which is free for more than the eighth of an inch. 



From Pebas ; J. Hauxwell's coll. 



HoLOTAXis MELANOSTOMTJs. Cope gen. et sp. nov. 



Cliar. Qenerieus No adipose fin ; origin of dorsal fin posterior to 

 that of the ventral. Teeth on the premaxillary, maxillary and man- 

 dibular bones, all simple conic, those of the first and last, in two rows. 

 Suborbital bones very large ; gill opening large. Scales without lateral 

 line. 



This genus is simply Pyrrhulina with maxillary teeth. 

 Character specificvs. Eather elongate; depth .0125 M.; length .07 M., 

 length of head .014 M.; width of do. behind .0065 M. Radii D. 9.; A. I. 

 10 ; V. 8. Scales 7 — 25. Above brownish, below yellowish ; on the sides 

 the scales with orange bases and brown edges forming longitudinal lines. 

 A black band through the operculum and orbit round the edge of the 

 premaxillary ; another I'ound the edge of the mandible. A black spot on 

 the middle of the dorsal fin. 



This species is evidently near the Pyrrhulina filamentosa of Cuv. and 

 Val., but the caudal fin is regularly emarginate, and has not the peculiar 

 form ascribed to that species by those authors. 



Numerous specimens from Pebas, Equador, Hauxwell's coll. 



Plethodectes erythrurtjs. Cope gen. et sp. nov. 

 Character genericus. Adipose fin present, dorsal short, originating 



above the ventrals. Anal short. Lateral line present on the inferior row 

 of scales ; belly not compressed ; gill opening wide. Teeth on the max- 

 illary, premaxillary and dentary bones. Maxillaries in one row, simple, 

 conic ; premaxillaries in two rows, those of the external simple conic, of 

 the inner tricuspid ; mandibulars in an outer row of tricuspid teeth, and 

 two simple conic in the middle behind them. Maxillary arch angulate, 

 the maxillary bones extending downwards on each side of the dentary. 

 This genus appears to be nearest to Piabucina Cuv. Val. It differs in 



