'74 



Series Ostariophysi 



body, and jet-black coloration, which comes up the smaller 

 rivers tributary to the Mississippi and Ohio in large numbers 



Flo. 137. Common Sucker, Catostomus commersoni (Le Sueur). Ecorse, Mich. 



in the spring. Most of the other suckers belong to the genera 

 Catostomus and Moxostoma, the latter with the large-toothed 

 Placopharynx being known, from the red color of the fins, as 



FIG. 138. California Sucker, Catostomus occidentalis Agassiz. (Photograph by 



Cloudsley Rutter.) 



red-horse, the former as sucker. Some of the species are very 

 widely distributed, two of them (Catostomus commersoni, Eri- 

 myzon sucetta] being found in almost every stream east of the 

 Rocky Mountains and Catostomus Catostomus throughout Canada 

 to the Arctic Sea. The most peculiar of the suckers in appear- 

 ance is the harelip sucker (Quassilabia lacera) of the Western 

 rivers. Very singular in form is the hump-back or razor-back 

 sucker of the Colorado, Xyrauchen cypho. 



Fossil Cyprinidae. Fossil Cyprinidce, closely related to exist- 

 ing forms, are found in abundance in fresh-water deposits of the 

 Tertiary, but rarely if ever earlier than the Miocene. Cyprinus 



