444 CALIFORNIA ACADEMY OF SCIENCES. 



433. Chsetostomus erinaceus. 



HyiJOfstomus erinaceus Cuv. & Val. Hist. Nat. Poiss, xv, 510, 1840 

 (Chile); Gay, Hist. Chile, ii, 308, 1848 (Chile). 



Chcetosiomus erinaceus Giinther, v, 249, 1864 (copied); Eigeum. & 

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



434. Chaetostomus bufonius. 



H upostomus bufonius Cuv. & Val. Hist. Nat. Poiss, xv, 511, 1840 



(Eio Apurimac, at an altitude of 2,000 meters). 

 Chfetostonrns bufonius Eigenm. & Eigenm. 1. c, 



435- Chaetostomus gymnorhynchus. 



A'cistrus gymnorhynchus Kner, Hypostomiden, 275, 1853 (Puerto 



Cabello). 

 Ch'i'tostomus gymnorhynchus Giinther, v, 259, 1864 (copied); Litt- 



ken, Vid. Medd. 1873, No. 13, 204 (Puerto Cabello); Eigenm. & 



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

 Hypostomus korsieni Kroyer, MS. 



XCIV. Ancistrus. 



AncistriLS Kner, Hypostomiden 272, 1853 (sp). 



Ancistrus Bleeker, Nederl. Tijdschr. Dierk. i, 1863, 77 

 (cirrJiosus). 



Type: Hypostovius cirrhosus Cuv. & Val. 



In this genus are included all those species of Plecos- 

 tomince whose snout is provided with tentacles. The 

 tentacles in some species are constantly present in both 

 sexes even in the very young and the. character may be 

 considered of generic value. 



Habitat: La Plata to Surinam. 



All the species of this genus are very much alike and 

 it would be mostly a mere repetition of words to describe 

 them in full. The following key will give all the essen- 

 tial points. 



ANALYSIS OF THK SPECIES OF ANCISTRUS. 



a. Margin of the snout naked, provided with tentacles. The females with 

 a narrow naked margin and a single series of simple tentacles or with- 

 out tentacles in calamita; males with a much wider naked area, a series 

 of simple marginal tentacles and a Y-shajDed series on the middle of the 

 snout. Thorax and belly naked; scutes of the body not keeled; region 

 between eyes and gill-opening partially naked; opercle erectile; head 

 broad, depressed, without keels. 



