HYBERNATION OF THE SNAIL. ' 199 



lays its eggs in shady places, in hollows which it excavates 

 and covers with its foot; the young at first lives entirely upon 

 the pellicle or thin skin of the egg 1 , and remains concealed in 

 its retreat a month before its shell is sufficiently hardened to 

 encounter its enemies. When the first chills of autumn ap- 

 proach, the snail prepares its winter habitation. 



FREDERICK. 



How is that made 1 ? 



ESTHER. 



In this manner. A quantity of viscid mucus or slime is 

 secreted in the under surface of the foot, to which a large 

 portion of the dead leaves adheres. This is turned on one 

 side, and a fresh secretion being thrown out, the layer of earth 

 mixed with mucus, is left. The animal then takes another 

 layer of earth on the bottom of the foot, turns it also to the 

 part where it intends to form the wall of its habitation, and 

 leaves it in the same manner, repeating the process until the 

 cavity is sufficiently large, and thus making the surface even 

 and compact. In forming the dome or arch of the form, a 

 similar method is used, the foot collecting on its under sur- 

 face a quantity of earth, and the animal, turning it upwards, 

 leaves it by throwing out fresh slime; and this is repeated 

 until the perfect roof is formed.* Having now completed its 

 winter house, the snail draws in its foot, covering it with the 

 mouth, and opens its spiracle to draw in the air; on closing 

 this, it forms with its slime a fine membrane, interposed be- 

 tween the mouth and extraneous substances. Soon after- 

 wards, the mouth secretes a large portion of a very white 

 fluid over its whole surface, which instantly sets uniformly, 

 and forms a kind of solid operculum, like plaster of Paris, 

 about half a line in thickness, which accurately closes the 

 mouth. When this is become hard, the animal separates the 

 mantle from it. After a time, expelling a portion of the air 

 it had inspired, and thus being reduced in bulk, it retreats a 

 little further into the shell, and forms another leaf of mucus, 



* Journal of the Royal Institution. 



