250 THE DISPERSAL OF SHELLS. 



East of the Arun there are few traces of the old forest, 

 and I have not yet come across this snail. In the 

 extensive beech woods on the top of the Downs the 

 species is nearly always absent, but most of these woods 

 have been planted within the last hundred years, and 

 the few relics of old forest are on ground liable to 

 become sodden in the winter. Helix ohvoliita has 

 been recorded from Kingley Vale, on the south 

 slope of the Downs. I could not find it there myself; 

 but it occurs in a copse about four miles to the 

 north. 



" Everything seems to show that the creature is a 

 relic of our old woodland fauna, now nearly exter- 

 minated through the destruction of the forests.^' 



Testacella haliotidea Drap. Gray (1840) 

 coupled this snail-slug with Dreissena polymorpJia as a 

 species supposed to have been introduced in modern 

 times, but he regarded it as well naturalized, and pos- 

 sibly indigenous. Jeffreys (1862) thought it almost 

 impossible to say whether the creature was a native or 

 had been introduced, but Mr. Rimmer has, more recently, 

 expressed the opinion that there are "some grounds 

 for believing it to be indigenous ; " he remarks, how- 

 ever, that it has doubtless been unintentionally imported, 

 from time to time, from abroad in soil at the roots of 

 shrubs and other plants. Mr. Alder, as long ago as 

 1838^ thought it might be reasonably regarded as a 

 native. Testacella sciitiilinn Sby. which appears in the 

 new British list as a distinct species, has been included, 

 for a long time and until quite recently, under T, halio- 



