FISHES 65 



spinous and 7 soft rays in the anal tin: Asia and Europe, first domesti- 

 cated in China; in many ponds and streams in the eastern States. 



3. Campostoma Agassiz. Body elongate; teeth with an oblique 

 grinding surface and a slight hook; air bladder surrounded by numerous 

 convolution of the very long alimentary canal, an anatomical feature 

 found only in this genus of fishes: 4 species, i in Mexico. 



Key to the United States Species of Campostoma 



ai In the eastern and central parts of the country C. anomalum. 



a2 In Texas C. formulosum. 



cix In .-\rizonia C. ornatum. 



C. anomalum (Rafinesque). Stone roller. Length 200 mm. or 

 less; head 4.2; depth 4.4; color brownish, with a brassy lustre and a 

 dusky vertical bar behind the opercle; dorsal and anal fin each with a 

 dark cross bar; male in spring with many tubercles; rays of dorsal fin 

 8; anal 7; scales 7-53-8: New York to Michigan, southward to Georgia 

 and Texas; westward to Wyoming; abundant in small streams; 

 herbivorous. 



C . formulosum Girard. Head short, with a projecting snout; head 4; 

 depth 4.5 ; color grayish, with a black spot at the base of the tail and one 

 on the dorsal fin; scales 46: Texas, from the San Antonio to the Rio 

 Grande. 



C. ornatum Girard. Length 85 mm.; head 3.75; depth 4; color 

 like C. anomalum; scales 10-75-9, 3 2 before the dorsal: southern Arizona; 

 very common locally. 



4. Orthodon Girard. Body elongate; teeth 6-6 or 6-5, compressed 

 and nearly straight; scales very small; pseudobranchias absent: i species. 



O. microlepidotus (Ayres). Length 375 mm.; head 4; depth 4.5; 

 color olivaceous; rays of dorsal fin 9; anal 8; scales 21-105-12; teeth 

 very long: basin of lower Sacramento and San Joaquin; abundant. 



5. Acrocheilus Agassiz. Body elongate; teeth 4-5, hooked; jaws 

 each with a conspicuous, broad, straight, horny plate; size rather large: 

 I species. 



A . alutaceus Agassiz & Pickering. Chisel-mouth. Length 300 mm. ; 

 head 4.5; depth 4; color very dark, body studded with minute dark 

 points; rays of dorsal fin 10; anal 9; scales 20-85-16: basin of the lower 

 Columbia, as far up as Spokane and Shoshone Falls; southeastern 

 Oregon; abundant. 



6. Lavinia Girard. Body elliptical, compressed, with a slender 

 caudal peduncle; teeth 4-5 or 5-5, slightly hooked; size large: i species. 



