200 Bulletin 47, Ufiited States National Museum. 



usually present. No adipose fin. Dorsal fin short in all the American 

 species, elongate in many Old World forms. Ventral fins abdominal. Air 

 bladder usually large, commonly divided into an anterior and a posterior 

 lobe, not inclosed in a bony capsule, rarely wanting. Stomach with- 

 out appendages, appearing as a simple enlargement of the intestines. 

 Fishes mostly of moderate or small size, inhabiting the fresh waters of 

 the Old World and of North America. Genera about 200; species nearly 

 1,000; excessively abundant where found, both in individuals and species, 

 and, from their great uniformity in size, form, and coloration, constituting 

 one of the most difiicult groups in natural history in which to distinguish 

 genera and species. Our genera are mostly very closely related, and are 

 separated by characters which, although reasonably constant, are often 

 of slight structural importance. 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 Avith small tubercles, outgrowths from 

 the epidermis. The fins and lower 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, yellowisli, or black. 



It is not easy to arrange the genera of Cyprinid'ip in accordance with 

 possible lines of descent. The herbivorous species with straight teeth in 

 one series (as Ortliodou), are doubtless nearest the primitive type, which 

 has degenerated into weak forms like Hyhogyiathus. In like manner 

 NotrojJts seems to have degenerated from Leuciscus, and perhaps Hjihopsis 

 from Gohio. Such forms as Mylocheilus and Ptychocheilus doubtless 

 approach the original line of descent. The Old World Cyprinidie are at once 

 more primitive and more highly organized than American forms. The 

 Pacific Coast species approach the European types. (Cyprinid.e, part, 

 Giinther, Cat., vii, 25-339.) 



Note. — Young Ci/prinidw are usually more slender than adults of the 

 same species, and the eye is always much larger; they also frequently 

 show a black lateral stripe and caudal spot, which the adults may not 

 possess. In the following descriptions the rudimentary rays of dorsal 

 and anal are not counted. The fins and scalea are often, especially in 

 specimens living in small brooks, covered with round black specks, imma- 

 ture trematodes. These should not be mistaken for true-color markings. 



No progress can be made in the study of these fishes without careful 

 attention to the teeth, as the genera are largely based on dental charac- 

 ters. The pharyngeal bones in the smaller species can be removed by 

 inserting a pin (or, better, a small hook) through the gill opening, under 

 the shoulder girdle. The teeth should be carefully cleaned with a tooth- 

 brush, or, better, a jet of water, and when dry may be examined by any 

 small lens. In most cases a principal row of 4 or 5 larger teeth will be 

 found, in front of which is a set of 1 or 2 smaller ones. The two sides are 

 usually, but not always, symmetrical. Thus, "teeth 2, 4-5, 1," iudicates 

 two rows of teeth on each 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 other. 

 "Teeth 4-4" iudicates a single row of 4 on each pharyngeal bone, and so 

 on. 



In the Lcuciscine genera, these teeth, or the principal ones, are " rap- 

 tatorial," that is, hooked inward at the tips. A grinding or masticatory 

 surface is an excavated space or groove, usually at the base of the hook. 

 Sometimes the grinding surface is very narrow and confined to one or two 



