Number 112 Jui.y i, 1922 



OCCASIONAL PAPERS OF THE MUSEUM OF 

 ZOOLOGY 



UNIVERSITY OF MICHIGAN 



Ann Arbor, Michigan Published by the University 



ON THE NOMENCLATURE OF CERTAIN NORTH 

 AMERICAN NAIADES 



By a. E. Ortmann and Bryant Walker 



Much confusion still prevails with regard to the nomen- 

 clature of North American Naiades. Two papers of Simpson 

 (1900C and 1914) have done much to clear up the situation, 

 but a number of cases have been contested in recent times 

 and changes have been introduced or suggested. 



A final revision of the nomenclature has often been urged. 

 But since all attempts made to attain this object have been 

 rather unsatisfactory, the present writers have tried to come 

 to an understanding with regard to the disputed cases, and 

 the present paper is the outcome of their joint labors. 



The principal source of controversy has always been as to 

 the standing of the many species described by Rafinesque 

 between 1820 and 1831. It has seemed to us that the main 

 difficulty in nearly all previous opinions has been the reliance 

 upon the so-called Rafinesque-Poulson types without regard 

 to the provisions of the International Code of Nomenclature. 



