31. CYPRINIDiE. 145 



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

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

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

 time, different authors have proi)ose(l to throw most of these groups into 

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

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

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

 iins or various i)ortions 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 pre^•ailing color 

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

 black.* 

 (C'^^rriJfWcr, part, Giiutlier, vii, 25-339.) 



* Dorsal fm short, witliout developed spiue. 

 t Air-bladdor surrounded by many convolutions of tlio very long alimentary canai. 



(Cdnqxjstoniiiiw.) 

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



toueuin lila<lc. 



Cami'ohtoma, 71. 

 tt Air-bladder above the alimentary canal ; teeth one-rowed. {Chondroatoinhicv.) 

 t Intestinal canal elongate, more than twice the length of the body; teetli with 



grinding surface well 

 develojied ; peritoneum 

 usually black. 

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



5, stout, l)luntish, hook- 

 ed, and short. 



AciiociULiis, 7y. 

 BB. Jaws without horny plate. 



C. TeethG-G,8tronglycomi)ressed,knife-shai)ed ; pseudobranchiie none; ru- 

 dimentary caudal rays 

 greatly d(iv eloped; 

 scales very s:iiall. 



Orthodox, 73. 



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

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

 serting a y)in or a hook through the gill-opening, under the s'.umlder-girdle. The 

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

 may be examined by any small lens. In most cases a prinicipal low of 1 or f) 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. "Tcetli 4-4" indicates a single row of 4 on cacli 

 l>haryngeal bone. " Teetli 2, 4-5, 1 " indicates 2 rows of teclh on each side — on the onc^ 

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

 and 1 in the lesser. In the Levciscine genera these teeth, or the princiiml ones, are 

 raptatorial, that is, hooked inward at their tijis. A grinding or masticatory surface is 

 an excavated sjjacc or groove usually at the IJkse of the hook. A llattened or bev- 

 elled edge sometimes simulates a masticatory surface, and in some of the species tho 

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

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

 has been vorilied on typical exaini)les either by Professor Cope or the writers. 

 Bull. Nat. ilus. No. 1(J 10 



