12 



this substance to be disintegrated clam shells. The bivalves 

 were evidently brought there by the occupants of the fortress, 

 and were doubtless used for food by the besieged, as we know 

 that several desperate battles occurred in this vicinity about 

 the time of the French occupation, 



TERRESTRIAL MOLLUSKS. 



ORDER PULMONATA. 



SUBORDER GEOFHILA. 



Before describing the species common to the county, it will 

 be necessary to give my readers a general idea of the habits, 

 etc., of the snails. And I may say here that the facts noticed 

 by naturalists all over the country are very much alike. I liave 

 paid considerable attention to this subject and compared my 

 own observations with those of others. I have examined the 

 animals in their own natural lu)mos; and have also domesticated 

 them to the number of ten or twelve species on my premises 

 in Chicago, where at the present writing, some of them are 

 hibernating, or taking their annual sleep. At this time 1 have 

 a number in glass cases. A few have fastened themselves to 

 the walls of my library, while I have planted some in various 

 locations around the yard for the purpose of observing next 

 3'ear's crop and the variations of animals under domestication. 

 My first observation was MacrocycUs concava attempting to 

 make a comfortable meal of its inoffensive neighbor Jlelh-. 

 aUernata. The carnivorous propensiy of the species is well 

 known. Some of the species are more active than others 

 in their movements. ]My // aliernata have made frequent 

 attempts to escape from confinement. Most of those I have 

 are, however, generally passive and remain closely withdrawn 

 into the shell. The snails can live, it seems, a long lime with- 

 out food or moisture. Well autlicnticated instances of this are 

 on record and seem truly marvelou.s. I now have live species 

 that have been without food for several months, and I propose 

 to test their endurance further Extremes of temperature are 

 said to be fatal to snails. Most of the species are solitary in 

 their habits, living alone, beneath logs, leaves, and stones, or 



