100 Bulletin ^7, United States National Museum. 



86. CHiETOSTOMUS, Kner. 



Chmtostomux, Kner, Ilypostomidcn, 272, 1^(53, (lohorhynchns). 



This genus, as understood by Dr. Eigenmann, includes all the forms 

 allied to lIi)i)Oiitomas and Ilemianciatrus in which the snout is naked. The 

 numerous species are chiefly confined to mountain brooks in South America. 

 (xuiTV, bristle; oTo/ia, mouth.) 



a. Pectoral spine lonjjer than liead; eye 8}^ in liead, 3 in snout; iuteiopeiculai- spines short 

 and stout, 1 or 2 on each side. riscuEEi, 251). 



259. CHiETOSTOMUS FISCHERI, Steindachner. 



{Ooucuu.) 

 Head 3i ; depth 5f. D. I, 8; A. I, 5 ; V. I, 5; P. I, 6. Interopercle 

 with 1 or 2 short but very strong curved teeth on each side. Mouth broad. 

 Eye 8J in head, about 3 in snout. Pectoral spine very strong, longer 

 than head by 1 or 2 diameters of the eye ; ventral spine 11 to 2 diameters of 

 eye shorter than head; longest ray of caudal slightly longer than head. 

 Scales 23 or 24. Yellowish, with very many yellow dots ; fins with some 

 faint dark spots. Rio Mamoni, near Panama. (Steindachner.) (Named 

 for W. Fischer, who collected the type.) 



Chsetostomius fischeri, Steindachnek, Flussfische SUdamer., i, 14, 1879, Rio Mamoni. 



87. ANCISTRUS, Kner. 



Ancislriis, Kneu, Hypostomiden, 272, 1853, (cirrhosns:). 



This genus includes numerous species of catfishes, allied to Hypostomus, 

 with the snout provided with tentacles. These tentacles are usually 

 present in both sexes, even in the very young. {uyiaaTfjoc, a fishhook.) 



260. ANCISTRUS CHAGRESI, Eigenmann & Eigenmann. 



Eye 6 to 7^ in head. D. I, 7; A, 4 or 5. Scales 24. Margin of the 

 snout naked, provided with tentacles. Females with a narrow naked 

 margin and a series of simple tentacles ; male with a much wider naked 

 area and simple marginal tentacles ; thorax and belly naked ; scutes of 

 the body not keeled ; region between eyes and gill openings partly naked. 

 Opercle erectile ; head broad, depressed, with keels. Lower caudal lobe 

 scarcely longer than upjier ; margin of the caudal obliijuely truncate. 

 Preopercular spines 11 to 15. Breast with a small granular patch of spines. 

 Rio Chagres. (Eigenmann.) 

 Ancistriis chagresi, Eigenmann, Proc. Cal. Ac. Sci., 1889,47, Rio Chagres, Panama. 



Order N. PLECTOSPONDYLI. 

 (The Carp-like Fishes.) 



Soft -rayed or physostomous fishes with the parietals broad, distinct ; 

 pterotic normal; symplectic present; opercular bones all present ; meso- 

 coracoid present; no interclavicles ; the 4 anterior vertebra? much modified 

 and joined together, provided with the Weberiau apparatus or ossicula 



