444 MICHIGAN SURVEY, 1905. 



Family. Genus. Subgenus. Section. No. of species ^ 



Helicidce Polygyra Triodopsis 14 



Stenotrema 3 



Circinariidce Circinaria 1 



Zonitidce Omphalina 2 



Vitrina 1 



Vitrea Vitrea s. s 4 



Striatura 1 



Glyphyalina 2 



Paravitrea 1 



Euconulus 2 



Zonitoides Zonitoides s. s. . . 2 



Pseudohyalina. . . 4 



Gastrodonta 4 



L macidce Agriolimax 2 



Philomycidce Philomycus 1 



Pallifera 2 



End.dontidce Pyramidula. . . Patula 2 



Gonyodiscus 2 



Planogyra 1 



Helicodiscus 1 



Punctum 1 



Sphyradium ♦ 1 



SuccineidcB Succinea 3 



Pupillidce Strobilops 3 



Acanthinula Zoogenites 1 



Pupoides 1 



Pupillsi. 1 



Bifidaria Privatula 1 



Alhinula 2 



Vertigopsis 2 



Vertigo Vertigo s. s 6 



Vertilla 1 



Valloniidce Vallonia 3 



Cochlicopidce Cochlicopa 1 



Auriculidoe Carychium , 2 



81 



While it is possible that some of the species quoted by the earlier writers 

 as occurring in Michigan but which have not been recognized by later col- 

 lectors and have therefore been dropped from the present catalogue may 

 hereafter be found within our borders, and that new or additional ones may 

 be reported, yet it is not probable that the present list will be largely in- 

 creased. 



But, while in this particular our fauna can be said to have been well de- 

 veloped, our knowledge as to the distribution of the different species is 

 lamentably deficient. I have indicated on the accompanying chart (Plate 

 I) the number of species which have been reported from each of the coun- 

 ties of the state. From this it will be seen how small a part of the state 

 has been collected over with any sort of thoroughness. Of the fifteen coun- 

 ties in the upper peninsula, eight are not represented by even a single re- 

 ported species, while of the sixty-eight counties of the lower peninsula, the 



