Stearns — Fresh Water Mussel Shells. 69 



The late Dr. Cooper* regarded the West Coast mussels, Ano- 

 donta uxihlametensis, A. oregonensis and A. californiensis as va- 

 rieties of A. nuttalliana, the last named being the first in order of 

 description and publication by Dr. Lea in his Observations, etc., 

 thus endorsing my conclusions as previouslj^ published in 1882. t 

 Whether Dr. Lea's species and Dr. Trask's A. triangularis and 

 A. rotundata are simply mutations of nuttalliana or otherwise, 

 it is not necessary to discuss at the present moment. These 

 and numerous undcscribed mutations occur in a multitude of 

 localities, often in great alnmdance, in the above-named West- 

 ern basins and their tributaries, alike in running or still waters, 

 subject to various environmental conditions. 



* Catalogue of West American and many Foreign Shells, etc., printer! for the State 

 Mining Bureau, April, IS'.M, Sacramento, State Printing Office, IS94. 



t On the History and Distribution of tlic Fresh Water INlussels, and tlie Identity of 

 Certain Alleged Species. Proc. California Academy of Sciences, Kovember 20, 1882. 



