NUMBER I12 JULY 1, 1922 
OCCASIONAL PAPERS OF THE MUSEUM OF 
ZOOLOGY 
UNIVERSITY OF MICHIGAN 
ANN Arzor, MICHIGAN PUBLISHED BY THE UNIVERSITY 
ed. Oct 1 ej 22 
J 
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 
(1g900c 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. 
