346 Mr. C. T. Regan on the Fishes of the 



Depth of body 2-2^ iu the length, length of head 2?,-2|. 

 Snout not longer than eye, the diameter of which is 2§-3^ 

 in the length of head and equal to or greater than the inter- 

 orbital width. Depth of prseorbital |^ to a little more than ^ 

 the diameter of eye. Mouth oblique; lower jaw projecting; 

 maxillary extending to below anterior part or middle of eye; 

 praimaxillary processes extending to above posterior margin 

 of eye ; cheek with 2 or 3 series of scales, none on the prae- 

 operculura; 10-11 gill-rakers on the lower part of anterior 

 arch. Scales 23-24 J-g, ^ a scale between lateral line and 

 anterior rays of soft dorsal. Dorsal XIII-XIV 9-11, com- 

 mencing above the opercular cleft, the spines increasing in 

 length to the last, Mliich is ^ the length of head, the soft fin 

 pointed, extending to middleor posterior extremity of caudal. 

 Anal III 8-9. Dorsal and anal fins scalcless. Pectoral 

 longer than the head, extending to above middle of anal. 

 Caudal rounded. Caudal peduncle .^-3 as long as deep. 

 Erownish ; a blackish spot on the middle of the side, another 

 at the origin of the lateral line, a third below the posterior 

 part of eye, and a fourth on the angle of the prseoperculum, 

 the last often ocellated ; a dark spot on the upper ^ of the 

 base of caudal ; soft vertical fins usually with small dark 

 spots. 



U. Amazon ; R. Orinoco ; Guiana. 



1. (152 mm.) R. Cupai. 



2. {l40 mm.) Demerara. F. G. Beckford, Esq. 



3. (Skeleton.) Teffe. Mus. Comp. Zool. 



4. (195 mm.) Tonantius. Paris Museum. 



ASTRONOTUS. 



Astronotus, Swains. Nat. Hist. Fish. ii. p. 229 (1839); Pellegr. M^m. 



Soc. Zool. France, xvi. 1903, p. 182 (1904). 

 Acara (part), Heck. Ana. Mus. Wien, ii. 1840, p. 338. 

 Hyyrogo7ins, Giinth. Cat. Fish. iv. p. 303 (1862). 

 Astronotus (part.), Eigenm. & Bray, Auu. Ac. N. York, vii. 1894, 



p. 615. 



Body ovate, compressed ; scales rather large, ctenoid. 

 Two lateral lines. Mouth moderate ; maxillary scarcely 

 exposed ; jaws with small conical teeth in bands and with an 

 outer series of rather strong teeth ; upper surface of head 

 scaly to between the orbits ; cheeks and opercular bones 

 scaly ; prseoperculum entire. Gill-rakers few and short. 

 A single dorsal, with XII-XIV 19-21 rays ; anal with 

 111 15-16 rays ; soft vertical fins densely covered with small 



