cri*KlNIUJi. 



Fam. 17. CYPRINID^. 



Cyprinidae, Ayassiz, Poiss, Foss. v. p. 5. 



Body generally covered with scales, head naked. 

 Margin of the upper jaw formed by the intermaxil- 

 laries. Belly rounded, or, if trenchant, without ossi- 

 cles. No adipose fin. Stomach without blind sac. 

 Pyloric appendages none. Mouth toothless ; lower 

 pharyngeal bones well developed, falciform, subparallel 

 to the branchial arches, provided with teeth, which are 

 arranged in one, two, or three series. Air-bladder 

 large, divided into an anterior and posterior portion 

 by a constriction, or into a right and left portion, en- 

 closed in an osseous capsule ; absent in Homalo]}tera. 

 Ovarian sacs closed. 



Fresh waters of the Old World and North America. 



We fii-st give a synopsis of the gi'oups, and then one of the genera. 



Synopsis of the Groups. 



I. Air-bladder divided into an anterior and posterior portion, not 

 enclosed in an osseous capsule. Barbels 0-4. 



A. Phaiyngeal teeth in a single series, exceedingly numerous, and 



closely set. Dorsal fin elongate, opposite to ventrals ; anal 

 fin short. Barbels none. 1. Catostomina, p. 12. 



(Gen. 1-4.) 



B. Pharyngeal teeth in a single, double, or triple series, in small 



number, the outer series never containing more than seven 

 teeth. 



1. Anal fin very short, with five or six (exceptionally seven) 

 branched rays. 



a. Lateral line running along the median line of the tail. 



Dorsal fin opposite to ventrMls. 



2. Cyprinina, p. 25. 



(Gen. 5-43.) 



b. Lateral line ninning along the median line of the tail. 



Dorsal fin inserted behind the ventrals. 



3. Rohteichthyiua, p. lUl. 



(Gen. 41.) 



