Vol. XXII, pp. 211-214 December 31, 1909 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



J L 



ON THE VALIDITY OF THE NORTH AMERICAN >'^. 

 CYPRINID GENUS NOTEMIGONUS. ^' 



BY T. D. A. COCKERELL. 



C 'h 



The genus Notemigonus Rafinesque 1819 (type auratus = 

 chrysoleucas) has in recent years been treated, not without 

 doubt, as a subgenus of Abramis, from which it is said to difTer 

 by the much shorter anal fin with 9 to 18 rays instead of 20 to 

 40 (Jordan and Everniann, Fishes of North and Middle 

 America, Part 1, p. 250). 



A study of the scales shows, I think conclusively, that 

 Notemigonus is really very distinct from Abramis. Notemigonus 

 chrysoleucas (Mitchill) is a rather small fish with relatively, but 

 not absolutely, large scales, which agree closely with those of 

 Opsopoeodus* ( 0. osculus Evermann ) . The genus also agrees with 

 Oj)soj)oeodvs in its serrate or crenate pharyngeal teeth, and I 

 consider the tw^o to be closely allied, forming a little group. 

 The scales of both are thin and broad, with the nuclear area 

 subbasal, the radii all apical, few and far apart, and the apical 

 circuli very far apart (for circuli), especially in N. chrysoleucas. 



The type oi Abramis Cuvier, 1817, is A. brama. Tliis is a large fish 

 with great subquadrate yellowish scales, in a specimen before me (Lougli 

 Erne, Maj. H. Trevelyan ; Brit. Mus. ) 18 mm. long and 21)^ broad. 

 The circnli are innumerable and extremely dense in the manner of so 

 many Old World cyprinids. The nuclear area is practically central; and 

 the radii, which are all apical are extremely numerous and close together, 

 in the middle actually G or 7 to a millimeter ! It would be difficult to 

 imagine a scale with any cyprinid f(;atures, more totally diverse from that 

 of Notemigonus. The pharyngeal teeth of Abramis brama are also diverse 

 from those of Notemigonus, and are not serrate or crenulate. 



• See Proc. Biol. Soc. Wash., XXII (1909), PL III, for 0. osculus. 



35— Peoc. Biol. Soc. Wash., XXII, 1909. (211) 



