14 MANUAL OF THE MOLLUSCA. 
had been more than a year out of water.* The pond-snails 
(ampullarie) have been found alive in logs of mahogany from 
Honduras (Mr. Pickering) ; and M. Caillaud carried some from 
Egypt to Paris packed in saw-dust. Indeed, it is not easy to 
ascertain the limit of their endurance; for Mr. Laidlay haying 
placed a number in a drawer for this purpose, found them alive 
after five years, although in the warm climate of Calcutta. The 
cyclostomas, which are also operculated, are well known to survive 
imprisonments of many months; but in the ordinary land- 
snails such cases are more remarkable. Some of the large 
tropical bulimi, brought by Lieutenant Graves from Valparaiso, 
revived after being packed, some for thirteen, others for twenty 
months. In 1849 Mr. Pickering receiyed from Mr. Wollaston 
a basket-full of Madeira snails (of twenty or thirty different 
species), three-fourths of which proved to be alive after several 
months’ confinement, including a sea yoyage. Mr. Wollaston 
has himself told us that specimens of two Madeira snails (helix 
papilio and tectiformis) survived a fast and imprisonment in 
pul-boxes of two years and a half, and that a large number of 
the small heli turricula, brought to England at the same time, 
were all living after haying been enclosed 1 in a dry bag for a 
vear and a half. 
But the most interesting example of resuscitation occurred to 
a specimen of the Desert snail, from Egypt, chronicled by Dr. 
Baird.t This individual was fixed to a tablet in the British 
Museum on the 25th of March, 1846; and on the 7th of March, 
1850, it was observed that he must have come out of his shell 
in the interval (as the paper had been discoloured, apparently 
in his attempt to get away); but finding escape impossible, had 
again retired, closing his aperture with the usual glistening 
film ; this led to his immersion in tepid water and marvellous 
recovery. Advantage was taken of this circumstance for making 
a sketch of the living animal (Fig. 2). 
The permanency of the shell-bearing races is effectually pro- 
vided for by their extreme fecundity; and though exposed to a 
hundred dangers in their early life enough suryive to re-people 
the land and sea abundantly. The spawn of a single doris may 
contain 600,000 eggs (Darwin); a river-mussel has been esti- 
mated to produce 300,000 young in one season, and the oyster 
cannot be much less prolific. The land-snails haye fewer enemies, 
and lay fewer eggs. 
* “Tt was alive 498 days after it was taken from the pond; and in the interim 
had been only twice for a few hours in water, to see if it was alive."—Rev. W. O, 
Newnham, ¢ Ann, Nat. Hist. 1850, 
