SOUTH AMERICAN NEMATOGNATHI. 441 



Barbels long, reaching nearly to the gill-openings. 



Lower surface of head covered with isolate granules; 

 ventral surface entirely granular. Lateral plates iso- 

 late, smallest at the base of the dorsal fin; each plate, 

 except on ventral surface of tail, with a median series 

 of strong spines; plates largest on dorsal and ventral 

 surfaces of the tail. 



Distance of dorsal spine from end of snout 2J in the 

 length; length of dorsal spine equal to head to upper 

 angle of gill-opening, its anterior surface covered witJi 

 short, stout spines; the dorsal rays frayed at tip, each 

 portion with a series of booklets. 



Caudal lunate, the outermost rays prolonged, longer 

 than dorsal spine. 



Pectoral spine very long and strong, about 2h in the 

 length, reaching past middle of ventrals, its entire outer 

 surface bearing short, stout spines; ventrals reaching 

 beyond origin of anal. 



Brown, sj)otted with darker; all the fins closely spotted 

 with darker, or almost barred. 



Head 2i; D. I, 8; A. I, 5; V. I, 5; P. I, 5; Lat. 1. 27. 



One specimen. No. 7752, length .71 m. Para. Pro- 

 fessor^Agassiz. 



415. Acanthicus genibarbis. 



Rhu'lcjiis (jenibarbls Cuv. & Val. xv, 484, pi. 453 ( ? Brazil); Schom- 



burgk, Fish. Brit. Guiana, part i, 136, 1841. 

 Acanthicus (jenibarhis Giluther, v, 253, 1864 (copied); Eigenm. & 



Eigenm. Proc. Cal. Acad. 2d Ser. ii, 46, 1889. 

 Habitat: ( ? ) 



This species is known only from the types in the Jar- 

 din des Plantes. 



XCIII. Ch.etostomus. 



<iHypo8tor)iu8 Cuv. & Val. xv, 1864. 

 <iAnci8trus Kner, Hypostomiden. 

 y^Chcvtosfomus Kner. 1. c. 



