102 THE DISPERSAL OF SHELLS. 



fresh shells, being at that time confined to the house 

 with a cold. Mr. Simon has also declared that he is 

 positive those were the shells he gave to him^ having 

 in his cabinet many more of the same sort, and nearly 

 of the same size." 



Dr. Johnston, who quoted this account in 1834, agreed 

 with Mr. Bingley in regarding the facts as well authen- 

 ticated, but the period during which the snails are said 

 to have remained torpid is exceptionally lengthy, and 

 I do not think that the evidence is quite conclusive. 



Helix DESERTORUM. — More satisfactory than the 

 foregoing is Dr. Baird's celebrated and often quoted 

 account of a desert sn lil [H. desertoruni) which re- 

 mained for four years fixed upon a tablet in the British 

 Museum, and subsequently revived and lived some time 

 in captivity. Two specimens which had been collected 

 in Egypt, it appears, were presented to the Museum in 

 March, 1846, and on the 25th of that month they were 

 fixed upon tablets and placed in the collection among 

 the other mollusca, where they remained till about the 

 15th of March, 1850, when owing to the fact that a 

 glassy-looking, and evidently recently-formed, epiphragm 

 was seen to have been formed in the mouth of one of 

 the shells, both were removed and placed in tepid 

 water, and, after the lapse of ten minutes, the animal of 

 one was seen to gradually come forth, and in a few 

 minutes more it was walking along the surface of the 

 basin in which it had been placed : next day it was 

 supplied with part of a cabbage-leaf of which it partook 

 readily though in small quantity, and on the 24th of 



