SOUTH AMERICAN NEMATOGNATHI. 417 



372, Rhinelepis aspera, 



Rhinelepis aspera Spix, Gen. et Spec. Pise. Bras. 4, pi. 2, 1829; Cuv. 



& Val. xv, 483, 1840 (Kio San Francisco); Schomburgk, Fish. 



Brit. Guiana, parti, 136, 1841; Giinther, v, 253, 1864 (copied); 



Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. ii, 42, 1889. 

 1 Rinelepis strigosa Cuv. & Val. xv, 480 (Parana); Schomburgk, Fish. 



Brit. Guiana, plrt i, 135, 1841. 

 Habitat: Rio San Francisco; ? Parana; ? Guiana. 



LXXXIV. HEMIANCISTRUS. 



<.Hypostomus Cuv. & Val. v, (sp.) 



<Ancistrus Kner, Hypostomiden (sp.) 



> Hemiancistrus Bleeker, Tijdschr. Dierk. i, 78, 1863 

 (medians). 



>Pseudacanthicus Bleeker, 1. c. 79 (serratus). 



<Chcetostomus Gunther, v, 240, 1864. 



Type: Ancistrus medians Kner. 



Habitat: La Plata; Amazon and its tributaries; Gui- 

 ana region; Pacific slope of Panama. 



We include in this genus all species of Plecostomini 

 having small teeth, a granular snout, remote dorsal fins 

 and an erectile spiniferous preopercle. All the species 

 of this genus seem to be rare, and our account of them 

 is limited to a mere list. 



Dr. Gunther unites in his genus Chmtostomus species 

 which are not as closely related to each other as some 

 are to other genera. Species with long marginal tenta- 

 cles on the snout certainly deserve to be separated from 

 others having granulations or spines instead of tentacles, 

 even if they do agree in possessing interopercular spines. 



373. Hemiancistrus serratus. 



Hypostomus serratus Cuv. &Val.xv, 503, 1840 (Surinam). 

 Pseudacanthicus serratus Bleeker, Nederl. Tijdschr. Dierkuiide, i, 



1863); id. Silures de Suriname, 13, pi. i, fig. 3, and pi. lii, fig. 



1, 1864 (Surinam). 



Chcetostomus serratus Giinther, v, 241, 1864 (ioc. ?). 

 Hemiancistrus serratus Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. 



ii, 43, 1889. 

 Habitat: Surinam. 



27 



