SEVEN-YEAR SLEEPERS 81 



under moss and leaves. Tlie heart tlien ceases perceptibly 

 to beat, but respiration continues in a very faint deforce. 

 The common garden snail closes the mouth of his shell 

 when he wants to hibernate, with a slimy covering' ; but he 

 leaves a very small hole in it somewhere, so as to allow a 

 little air to ^'et in, and keep up his breathing,' to a sli^'ht 

 amount. J\Iy experience has been, however, that a great 

 many snails go to sleep in this way, and never wake up 

 again. Either they get frozen to death, or else the respira- 

 tion Tails so low that it never picks itself up properly when 

 spring returns. In warm climates, it is during the sunnner 

 that mollusks and other mud-haunting creatures go to 

 sleep ; and when they get well plastered round with clay, 

 they almost approach in tenacity of life the mildest recorded 

 specimens of the toad-in-a-hole. 



For example, take the following cases, which I extract, 

 with needful simplifications, from Dr. Woodward. 



' In June 1850, a living pond mussel, which had been 

 more than a year out of water, was sent to Mr. Gray, from 

 Australia. The big pond snails of the tropics have been 

 found alive in logs of mahogany imported from Honduras ; 

 and M. Caillaud carried some from Egypt to Paris, packed 

 in sawdust. Indeed, it isn't easy to ascertain the limit of 

 their endurance ; for Mr. Laidlay, having placed a number 

 in a drawer for this very purpose, found them alive after 

 five years' toi'pidity, although in the warm climate of 

 Calcutta. The pretty snails called cyclostomas, which 

 have a lid to their shells, are well known to survive im- 

 prisonments of many months ; but in the ordinary open- 

 mouthed land-snails such cases are even more remarkable. 

 Several of the enormous tropical snails often used to decorate 

 cottage mantelpieces, brought by Lieutenant Greaves from 

 Valparaiso, revived after being packed, some for thirteen, 

 others for twenty months. In 1849, Mr. Pickering received 



