Fine- scaled Suckers 



known as the mountain sucker, is abundant in the streams in 

 the Salt Lake basin, and southwest in the Sevier basin. It 

 reaches 8 or 10 inches in length. P. plebeius reaches a foot in 

 length and is found in the Rio Grande basin and southward into 

 Chihuahua. It is very common. P. delphinus, the blue-headed 

 sucker, attains the length of a foot, and is abundant in the upper 

 portion of the basin of the Colorado. P. gu^maniensis is known 

 only from Lake Guzman, Chihuahua. P. jordani grows to a foot 

 or more in length, and is found pretty generally distributed in clear 

 streams in the upper portions of the Missouri and Columbia 

 basins. It is of more value as a food fish than any other species 

 of the genus. P. arceopus from the rivers of Nevada and the 

 Kern River, California, and P. clarhi from the Gila basin, are rare 

 and little known species. 



GENUS CATOSTOMUS IE SUEUR 

 Fine-scaled Suckers 



Body rather elongate, more or less fusiform, subterete; head 

 rather long; eye small and high up; mouth rather large, inferior; 

 upper lip thick, papillose, protractile; lower lip greatly developed, 

 with broad, free margin, usually deeply incised behind, so that it 

 forms two lobes which are often more or less separated; opercle 

 moderate; pharyngeal bones moderate, the teeth rather short, 

 compressed, rapidly diminishing in size upward; scales' small and 

 crowded anteriorly; lateral line nearly straight and well developed; 

 origin of dorsal nearly midway of body; anal short and high; 

 ventrals inserted under middle or posterior part of dorsal; caudal 

 forked, the lobes nearly equal; sexual peculiarities not marked, 

 the fins usually higher in the male and the anal somewhat 

 swollen and tuberculate in the spring; breeding males in most 

 species with a rosy or orange lateral band. 



Species about 20, all belonging to North America except one 

 (C. restrains TilesiusJ which is said to occur in Siberia. Our 

 species are not well differentiated and are difficult to distinguish. 



In the following key have been included only those which 

 are of commercial value: 



a. Head transversely convex above, the orbital rim not elevated; 

 scales in lateral line 60 or more. 



46 



