Series Ostariophysi 



163 



yngeals, which are scythe-shaped and in typical forms are armed 

 with a relatively small number of highly specialized teeth of 

 peculiar shape and arranged in one, two, or three rows. In 

 all the species the gill-openings are restricted to the sides ; there is 

 no adipose fin, and the broad, flat branchiostegals are but three 

 in number. In all the species the scales, if present, are cycloid, 

 and the ventral fins, of course, abdominal. The modification 

 of the four anterior vertebrae and their connection with the 

 air bladder are essentially as seen in the catfishes. 



The name Plectospondyli is often used for this group (rrXeKTos, 

 interwoven; o-7rovdi>Xos, vertebra), but that term originally in- 

 cluded the Characins as well. 



The Cyprinidae. The chief family of the Eventognathi and the 

 largest of all the families of fishes is that of Cyprinida, comprising 



FIG. 122. Pharyngeal bones and teeth of European Chub, Leuciscus cephalus 

 (Linmcus). (After Seelye.) 



200 genera and over 2000 species, found throughout the north tem- 

 perate zone but not extending to the Arctic Circle on the north, 

 nor much beyond the Tropic of Cancer on the south. In this 

 family belong all the fishes known as carp, dace, chub, roach, 

 bleak, minnow, bream, and shiner. The essential character of the 

 family lies in the presence of one, two, or three rows of highly 

 specialized teeth on the lower pharyngeals, the main row con- 

 taining 4, 5, 6, or 7 teeth, the others i to 3. The teeth of the 

 main row differ in form according to the food of the fish. They 

 maybe coarse and blunt, molar-like in those which feed on shells; 



