31. CYPRINID^E. 145 



which to distinguish genera and species. Our genera are mostly very 

 closely related, and are separated by characters which, although reason- 

 ably constant, are often of slight structural importance. From time to 

 time, different authors have proposed to throw most of these groups into 

 the genus Leuciscus, a procedure which, without further discussion, may 

 be said to have always led to confusion. The spring or breeding dress 

 of the male fishes is often peculiar. The top of the head, and often the 

 fins or various portions of the body, are covered with small tubercles, 

 outgrowths from the epidermis. The fins and parts of the body in the 

 spring males are often charged with bright pigment, the prevailing color 

 of which is red, although in some genera it is satin-white, yellowish, or 

 black.* 

 (Cyprinidas, part, Giinther, vii, 25-339.) 



* Dorsal fin short, without developed spine, 

 t Air-bladder surrounded by many convolutions of the very long alimentary cauai. 



( Campostomince. ) 



A. Teeth 4-4, or 1, 4-4, 0, with oblique grinding surface and slight hook; peri- 

 toneum black. 



CAMI-OSTOMA, 71. 



tt Air-bladder above the alimentary canal ; teeth one-rowed. (Clionilrostom'm(B.') 

 I Intestinal canal elongate, more than twice the length of the body ; teeth with 



grinding surface well 

 developed ; peritoneum 

 usually black. 



B. Jaws each with a conspicuous, broad, straight-edged, horny plate ; teeth 4- 



5, stout, bluutish, hook- 

 ed, and short. 



ACROCHILUS, 72. 



BB. Jaws without horny plate. 



C. Teeth 6-6, strongly compressed, knife-shaped ; pseudobranchise none; ru- 

 dimentary caudal rays 

 greatly developed; 

 scales very small. 



ORTHODOX, 73. 



* No progress can be made in the study of these fishes without a careful examina- 

 tion of the teeth. The pharyugeal bones in the smaller species can be removed by in- 

 serting a pin or a hook through the gill-opening, under the shoulder-girdle. The 

 teeth should be carefully cleaned with a tooth-brush, or a jet of water, or a pin, and 

 may be examined by any small lens. In most cases a principal row of 4 or 5 teeth 

 will be found, in front of which is sometimes a set of 1 or 2 smaller ones. The two 

 sides are not always symmetrical. "Teeth 4-4" indicates a single row of 4 on each 

 pharyngeal bone. " Teeth 2, 4-5, 1 " indicates 2 rows of teeth on euch side on the one 

 side 4 in the principal row and 2 in the lesser, on the other side 5 in the main row 

 and 1 in the lesser. In the Leuciscine genera these teeth, or the principal ones, are 

 raptalorial, that is, hooked inward at their tips. A grinding or masticatory surface is 

 an excavated space or groove usually at the base of the hook. A flattened or bev- 

 elled edge sometimes sinmlates a masticatory surface, and in some of the species- the 

 grinding surface is very narrow and confined to but one or two of the teeth. In all cases 

 where the number of teeth is given in the specific descriptions following, this number 

 has been verified on typical examples either by Professor Cope or the writers. 



Bull. Nat. Mus. No. 16 10 



