336 walker: shells of Michigan. 



A. fragilis Lam. A very common species and extremely 

 variable. No less than five forms (A. fiava, glandulosa, imbricata, 

 iftsans, and pallida) have been described as distinct by Anthony 

 and one {A. subcarinata), by Currier. 

 A. imbecilis Say. 



A. Marryatana Lea. A. sublnflata Anth. and A. Hough- 

 tonetisis, Cmrier, MSS., are forms of this species. 



A. modesta Lea. Purely a Michigan species. The type 

 specimen was found near Kalamagoo and the species has since 

 been found in other localities in the state. 



A. ovata Lea. One of Anthony's varieties, ^.i'/z^^i^/z^z/t/fl/dr, 

 is considered a form of this species. 

 A. Pepiniana Lea. Miles. 

 A. plana Lea. 

 A. salmonia Lea. 



A. Schafferiana Lea. Miles, Currier. 

 A. subcylindracea Lea. 



A. subglobosa Anth. Anthony, Currier. Of twelve 

 varieties of i^nodonta from this state described by Anthony as new 

 species, this is the only one considered as valid by Mr. Lea in his 

 last Synopsis. 



Spheerium sulcatum Lam. 



S. aureum Prime. Prime, Currier. The typical specimens 

 of this species are doubtfully referred to Lake Superior by Prime. 

 If that be the fact, the species will probably be found in the 

 northern j)art of the state. 

 S. solidulum Prime. 

 S. strialinum Lam. 

 S. rhomboideum Say. 

 S. fabale Prime. 

 S. occidentale Prime. 



S. emarginatum Prime. Prime, Currier. (Lake Superior) 

 S. flavum Prime. Prime, Currier. (Lake Superior.) 



J.C, ii., Nov., 1879 



