204 THE DISPERSAL OF SHELLS. 



snails are much in favour as " live sea stock," according 

 to Woodward's " Manual/^ have naturalized " Helix 

 aspersa in Algeria, the Azores, and Brazil, and Helix 

 lactea at Teneriffe and Montevideo.'^ ^ H. lactea is said 

 to be extremely common in the markets at Buenos 

 Ayres.^ Occasionally, as might be supposed, imported 

 edible snails are intentionally thrown out in the hope 

 that they may establish themselves. Helix poinatia, 

 as mentioned in the next chapter, is said by some 

 authors to have been thus established in England by 

 the Romans, and others say that it was subsequently 

 planted by our own countrymen who had imported it 

 either as a delicacy or for medicinal uses. Mr. Layard 

 assures me that Helix aspersa, now abounding about 

 Cape Town, first obtained a footing in this manner. 

 The following extract from a characteristic letter of his 

 — dealing also with the introduction of the creature into 

 the Loyalty Islands — will be read with interest : 



" In 1854 (or 1855, I am not sure which) I was living 

 in the 'Gardens,' that part of Cape Town running up 

 the slope of Table Mountain. I one day noticed in the 

 vineyard attached to my house, on a wall, a cluster of 

 young H. aspersa. Of course I knew at once they 

 must be an introduction. Soon complaints were made 

 of vines and vegetables being devoured by snails, and 

 as I was known to be a " snail collector," the introduc- 

 tion of the marauder was set down to me. This I at 

 once repudiated, and set to work to find out who had 



' Woodward's " Manual," ed. 4, rep. 1S90, p. 87. 

 ' W. H. Rush, " Nautilus," vi. (1892), p. 82. 



