PULMONATA. 6 



next spring's sun. During the months' of April or May, on the 

 accession of the first warm weather of the season, the animal 

 breaks down and devours the membranous partitions, and comes 

 forth to participate in the warmth and freshness of the season. 

 At first it is weak and inactive, but recovering in a short time its 

 appetite, resumes its former activity. 



The season of hybernation continues from four to six months. 

 The final cause of this extraordinary condition is undoubtedly to 

 enable the animal to resist successfully the .extreme reduction of 

 temperature, and to survive through the long period when it 

 must, in northern clifliates at least, be entirely destitute of its 

 usual food. With a view to the first purpose, a place of shelter 

 is provided, and the aperture of the shell is hermetically sealed 

 by the epiphragm or the hibernaculum ; for the second, the state 

 of torpor is adopted, during which the functions of digestion, 

 respiration, and circulation being suspended, and all the secre- 

 tions and excretions having ceased, there is no drain upon the 

 strength and vitality of the animal, and no exhaustion of its 

 forces. Hence it comes forth, at the end of the period, in much 

 the same condition in which it commenced it, and resumes almost 

 immediately its usual functions and habits. So entire is the 

 cessation of the function of respiration, that the air contained 

 between the epiphragm and the animal is found to be unchanged. 

 The circulation, how^ever, may be partially restored by a small 

 degree of heat, the warmth of the hand being sufficient to stimu- 

 late the heart to action. 



The snails pass the greater part of their lives under dead leaves 

 and logs, under stones, or burrowing in the ground. They seldom 

 come from their lurking places while the sun shines, and indeed 

 are never seen ranging in the daytime unless the day be damp 

 and dark. Should they then be surprised by the appearance of 

 the sun, they immediately take shelter from its rays, under some 

 cover or on the shaded side of the trunks of trees. 



Their natural food is vegetable ; and the formation of the mouth 

 and the organs with which it is armed seems to be peculiariy well 

 adapted for cutting fruits and the succulent leaves of plants. 

 The dental edge of the upper jaw being applied against the sub- 

 stance to be eaten, the semilunar rough instrument, which 



' In New England, earlier in more southern latitudes. 



