21 

 SUBGENUS STROBILA, Morse. 



Helix l:U»,rintUica, Say. SllcU COllic, elovatcd, 



apex blunt; wliiils six; capertiiro lunate, witli teeth 

 within ; color chestnut ; dia. 2^ mill ; height 2^ mill. 



This small species occurs in great abundanci^ in the 

 Fox River Valley, and may be known by its (elevated 

 conic shape. 



OK.^'lJS l»i;i»A, Dit.vr. 



This genus was founded by Draparnaud, to include 

 the minute species of Europe that had been classed 

 with the Helices, and by some is considered superJicial. 

 The genus has, however, been adopted as a good one. 

 The shells are so minut(5 as to require mu(;li time., 

 patience and skill to iind. My friend, Dr. L. N. 

 Dimmick, was very successful in finding them, as sev- 

 eral thousand specimens presented to me by him attest. 

 The habits of the species are semi-aquatic, being found 

 in damp or wet places, or near streams and frequently 

 on drift-wood in our rivers. 



SUBGENUS PUPILLA, Lkacii. 



i»i;i»A B»i:.\roi>t>>, s.w. 



Shell conical, ovate ; whirls five, well rounded with 

 deej) suture ; aperture semi-circulai- ; pcnistome sliai*]:) 

 and expanded ; has a callus on the inner margin of the 

 lip on which are from three to six denticles ; on the 

 parietal wall is oiu* i)rominent denticle: shell horn 

 color ; length 2.^^ mill. Very abundant. 



