448 MICHIGAN SURVEY, 1905. 



« 



This double bag apparatus can be carried in one hand, scoop in the other, 

 and employed around springs, creeks, etc., whenever a patch of alluvium is 

 seen, where Pisidia and other mud-loving species are likely to be found. 

 The inner bag will prevent vegetation, dead leaves and sodden twigs from 

 passing through into the outer one. When the bag is sufficiently heavy, 

 carry to water that is deep enough to permit it being soused up and down. 



Wash out everything that will pass through the inner bag and remove it. 

 Then continue sousing until all sand and mud is washed away. The com- 

 paratively small volume of material remaining may be partly or wholly 

 emptied into the scoop and, by careful immersion, agitation, raising and 

 lowering, the greater portion may be floated off, leaving the residue con- 

 sisting of pebbles and shells at the bottom. Empty these into a small 

 sack, and repeat procedure until satisfied with catch. 



When ready for home, empty contents of small sack into scoop and float 

 off still more debris. At home take a piece of Y' mesh wire netting 4'' or 

 5'' square, concaved with fingers, and remove large pebbles. Put remainder 

 into a dish and cover with alcohol. Let this stand for some hours, then 

 spread out thinly on a newspaper, allowing the material to become thor- 

 oughly dry. The alcohol not only kills the animal, but hardens the tissues 

 and contracts the muscles, so that comparatively few have gaping valves 

 later. With a jeweler's loupe and a pair of forceps the final separation may 

 be made when convenient. 



Frequently one will have large numbers of other shells: Amnicola, Val- 

 vata, Paludestrina, and an occasional Bifidaria or Vertigo. The inner bag may 

 be dispensed with when dead leaves and twigs are not abundant, and then 

 one will find some of the booty consisting of Planorhis, Physa, and Lymncea. 



WHERE TO COLLECT. 



, Everywhere. The land species love dampness and darkness. They are to 

 be looked for under logs, bark and leaves in suitable localities. Many 

 species bury themselves in rotten logs, and these should be broken up with 

 the hoe. The accumulation of dead leaves around fallen trees is a favorite 

 habitat and should also be carefully and slow^ly gone over with fingers and 

 hoe. The thick grass and dense thickets along the margin of ditches and 

 streams will usually reward a careful examination. Southern and western 

 exposures being dryer, are not so fruitful as eastern and northern hillsides 

 and shady ravines. Coniferous forests are usually quite barren of mol- 

 luscan life. An open hardwood forest in a limestone region is the ideal 

 hunting ground. Nearly every permanent body of water has its mollusks, 

 varying according to its character. Some species are found only in rapid 

 flowing water, and others only in ponds and still water. Ditches and other 

 stagnant waters are usually good collecting ground for Pisidia and other 

 small species. The low places in the woods, which dry up in the summer 

 time, have a number of species that are not found elsewhere, and which 

 bury themselves in the mud when the water disappears. Sand banks in 

 rivers and lakes are the favorite resort of many of the smaller species. The 

 under side of the lily pads should be scrutinized, while the Ancyli should be 

 looked for on stones and dead clam shells. 



