170 BULLETIN UNIVERSITY OF MONTANA 



MONTANA SHELLS. 



The following list comprises the land and fresh water shells reported 

 from the state. The list contains 60 species and varieties, 25 of which 

 have been collected west of the main range of the Rocky Mountains, 42 

 east of the range. This makes a list of seven found on both sides of the 

 Rocky mountains. 



The collection east of the range was made largely by Homer Squyer, 

 of Wibaux, recorded in Nautilus, Vol. VIII, pp. 63-65. At the time the 

 record was made the town was called Mingusville, since changed to Wi- 

 baux. The shells from Madison Lakes and Tobacco Root Mountains were 

 collected by Earl Douglas and E. H. Murray. Those on the western slope 

 were all collected by the writer. 



The list certainly does not represent the entire mulluscan fauna of 

 the state, and is given merely as a basis for work, so that those interested 

 in these forms may be able to work intelligently. Residents of the state 

 are invited to send to the writer shells from their localities, so as to aid 

 in making a complete list. 



Full information and notes regarding these shells are to be found in 

 the articles mentioned in the appended Bibliography. 



It will be observed that the shells collected are from extreme ends 

 of the state, with a few only from the interior. As the state is about 

 600 miles long there is consequently an extensive area intervening be- 

 tween the two collecting fields which yet awaits study. 



The writer is under many obligations to Dr. W. H. Dall, of the Smith- 

 sonian Institute, and Dr. H. A. Pilsbry, of the Philadelphia Academy of 

 Science, for their valuable assistance, so freely and cheerfully given, in 

 the determination of specimens. 



PHYLUM MOLLUSCA. 



Class LAMELLIBRANCHIATA. 



Order Siphonata. 



Family CYCLADIDAE. 



Genus Sphaerium. 



Sphaerium sulcatum Lam.; Wibaux. 



Sphaerium partumeium Say; Daphnia Pond, Swan Lake. 



Genus Pisidium. 

 Pisidium compressum Prime; Wibaux. 



Order Asiphonata. 

 Family UNIONIDAE. 

 Genus Anodonta. 



Anodonta plana Lea; young, Wib?iux. 



