24 



the middle of tlie columella, about midway between 

 the extremities of the lip ; color white, appearance 

 shining ; length 1^ mill. Dia. mill. 



This minute species was described by Say as a Pupa, 

 in 1822, and is still known as such to many collectors. 

 In 1851, Dr. Wm. Stimpson pointed out its tru(i posi- 

 tion— " Shells of New England." This is the most 

 abundant of all our minute species. They may 

 be found in wet moss, leaves, bark, drift-wood, etc., 

 along our rivers. Dr. L. N. Dimmick has collected 

 mail}' thousands in the vicinity of Ottawa. 



i'a:^ii i.v i.in.^\i<:ii> i:. 



The LimncBldat are found all over tlie world. They 

 are very variable in tlieir characters, and as yet imper- 

 fectly understood. In habits they are aquatic, and 

 are found in rivers, j^onds, and creeks. They feed on 

 vegetable matter or the slimy material found in rivers, 

 and on infusorial animalcuhx). Dr. Gould speaks of 

 tliem eating each others' shells in the latter part of the 

 warm season. Having myself kej^t them alive for 

 months at a time, I am able to confirm Dr. Gould's 

 statement as far as this. Tliey rasp off* with their 

 tongue the confervaceous vegetation and ejndermis of 

 each others' shells in a V(?ry thorough manner. The 

 sexes are united in the sanu> individual. The shell is 

 dextra.1, with a fold upon the columella. Tlun' com(^ 

 to the surface to breath free air, but are adapted to 

 breathing through water. On the api)roach of cold 

 weather they bury themselves in the mud for tlu^ win- 

 ter. From my own observation, tliey begin to dis- 



