I nio ligamentinus Lam. 

 •parvus Bar. 

 plica tus Lea. 

 pustulosus Lea. 



rectus Lam. 



Two others have not been found in the extreme south- 

 eastern part of the state, viz: 



Unio spatulatus Lea. 

 trigonus Lea. 



Omitting - these species, whose distribution is apparently 

 restricted to a greater or less degree, we have a remainder of 

 five species which have a general range over the whole 

 southern portion of the state. They are 



Unio coccincus Hild. 

 rubiginosus Lea. 

 triangularis Lea. 

 undulatus Bar. 

 verrucosus Bar. 



MARGARITINA. 



Of the five species of these genus, two range over the 

 whole state, viz: 



Margaritina dcltoidea Lea. 

 rugosa Bar. 



One, Margaritina hihlrcthiana Lea, has thus far been 

 found only in Wa}*ne and Monroe counties, in the southeast- 

 ern corner. 



Margaritina complanata Bar, has not been found outside 

 of the Saginaw-Grand valley, except in one locality, the 

 River Rouge, near Detroit. 



Margaritina marginata Say, is apparently of general 

 distribution through the southern part of the state and has 

 been found as far north as Houghton Lake, Roscommon 

 county, the source of the Muskegon river. 



ANODONTA. 



Any satisfactory consideration at the present time of the 

 distribution of the species of this genus is rendered very diffi- 

 cult by the extreme variability of nearly all of the species, 

 the lack of authentic specimens in the hands of local collect- 

 ors as a basis for identification and the consequent uncertain- 

 ty as to the reliability of many of the citations, which have 



