6Q THE NAUTILUS. 



S. solidulum Prime. Houghton Lake, Roscommon County ; iden- 

 tified by Dr. James Lewis. 



S. styiatinum Lam. Very abundant everywhere and equally 

 variable. 



S. rhoviboideum Say. Appears to be generally but not abun- 

 dantly distributed through the southern part of the State. 



S.fabale Prime. Not common but ranges over the State. 



S. occidentale Prime. Quite common. 



S. emargimdnvx Prime. The types are said to have come from 

 the region of Lake Superior. Cited by Currier and De Camp ; 

 but apparently on the strength of Prime's statement. 



S. flavum Prime. Types from Sault Ste. Marie. Cited by Cur- 

 rier (" Lake Superior ") and De Camp. 



S. jmrtumeium Prime. Cited by Currier and De Camp from 

 Lake Superior, apparently from the statement given by Prime in 

 his original description. The citation from Houghton Lake in my 

 catalogue of 1879, is erroneous, as the specimen does not agree with 

 examples, supposed to be authentic, received from other localities. 



S. sphcericuvi Anth. Grand Traverse County and Fenton, Mich- 

 igan, identified by H. A. Pilsbry. Other examples from the latter 

 locality are referred to S. secure by E. W. Roper (Nautilus, iv, 

 p. 40). 



S. transversiim Say. Rouge River, Wayne County. Cited by 

 De Camp from Grand River, Kent County. 



S. secure Prime. Generally distributed through the State. 



S. secure crocea Lewis. ' Traverse City ; see Roper, Nautilus, iv, 

 p. 40. 



S. truncatum Lind. Generally distributed through the State. 



;S^. vermontanum Prime. Cited by De Camp. 



S. romceum Prime. Cited by De Camp. 



S. stamineum Con. Western part of the State. 



S. tenue Prime. Cited by De Camp. 



Pisidum virginicum Bgt. Cited in all the lists and apparently 

 distributed over the State. 



P. adamsi Prime. Cited by Prime from Holly. Cited also by 

 Currier and De Camp. 



P. compressnm Prime. Abundant everywhere. 



P. abditum Hald. Common everywhere. 



P. abditum abyssorum Stimp. Common in Lake Superior at a 

 depth of from 4 to 159 fathoms according to Smith. Originally 

 described from Lake Michigan specimens. 



