116 'Natural History of Molluscous Animals : — 



account of the hybernation of Helix pomatia, in the first 

 volume of the Zoological Journal ; to which I must refer you 

 for the particulars. This species forms, by aid of its foot and 

 a very glutinous secretion, an excavation or nest, in which it 

 buries the shell, and it then closes the aperture with a thick 

 calcareous epiphragm, and with several interior membranous 

 partitions, which are more numerous at the end than at the 

 beginning of winter, and in the snails inhabiting the moun- 

 tains than in those found on low ground. Thus buried and 

 enclosed, it passes six months in a state of total torpidity ; 

 for the only indication of irritability perceptible during this 

 period is a slight contraction of the collar of the mantle when 

 touched, on removing the epiphragm. He found that there 

 was no digestion ; the heart at first beat feebly, and with a 

 very slow pulsation; but at a later period it was found to 

 have stopped, and the circulation was entirely suspended; 

 respiration ceased ; no animal heat, which even in the sum- 

 mer, when respiration and circulation are most lively, does 

 not exceed one degree above the surrounding atmosphere, 

 was evolved; no secretions nor wasting function went on, 

 neither any growth or reproduction of new parts. " In our 

 climate, it is about the beginning of April, soon after the song 

 of the cuckoo begins and the swallows appear, that the snails 

 leave their torpid state; varying a little, however, according 

 to the season. The mode by which their escape from con- 

 finement is effected is simple and easily comprehended. The 

 air which is contained in the different cells, and which had 

 been expired on the animal withdrawing itself farther and 

 farther into the shell after the formation of the operculum, is 

 again inspired, and each separate membranous partition 

 broken by the pressure of the hinder part of the foot pro- 

 jected through the mantle. When it arrives at the calcareous 

 operculum, the animal, making a last effort, bursts and detaches 

 its most obtuse angle. Then insinuating by little and little 

 the edge of the foot between the shell and the operculum, it 

 forces the latter off, or breaks it away. The animal then 

 comes forth, walks, and immediately begins feeding, with an 

 appetite excited, doubtless, by an abstinence of six or seven 

 months." (p. 99.) 



Such is M. Gaspard's account of the reviviscency of Helix 

 pomatia, and the process must be still simpler in the other 

 species; for they have merely to rupture a single horny or 

 semigelatinous membrane. But there has been a difference 

 of opinion relative to the source of the air which is first 

 respired. Gaspard, you will observe, says that that portion 

 which is confined between the layers of the epiphragms is 



