PEARCE : VARIETIES OF BANDED SNAILS. 1 29 



But in the places which have not been used as sheep-pastures 

 the numbers prove very different : — 



PLACE. VAR. ornata. MOTTLED VAR. 



Burnham and Berrow Sand-hills, ) i. ... 66. 



Somerset, Oct., 1888 ) 5. ... 85. 



Isle of Wight Downs, Sept., 18S7 ... 4. ... 14. 



South Devon, near Torcjuay, ) 



Aug., 1888 I °- ••■ '• 



Totals ... 10. ... 192. 



Thus in the pastures, though tliere are always a large 

 number of the mottled form of Helix caperata, at the same 

 time the var. oniata always proves nearly as numerous, at times 

 more so than the mottled form. Whereas in localities where 

 there is no sheep-feeding the var. ornata all but entirely dis- 

 appears, and the mottled forms are exclusively found. 



If, then, we conclude that the variety ornata is practically 

 restricted in this way to sheep-pastures, we seek further to know 

 how sheep can have in any way aided in the production of this so 

 conspicuous a variety of Helix caperata on their feeding grounds. 



There is only one way by which it is conceivable that 

 sheep can unknowingly effect any result. Remembering the 

 great abundance f)f Helix caperata on the turf of our downs, 

 and that the sheep, as they browse in solid compact flocks of 

 several hundreds, in cropping the grass they must, of necessity, 

 eat many and many an unseen snail, shell and all, whether of 

 Helix caperata or Helix virgata. 



That the sheep in feeding devour many a snail with the 

 grass is a fact, and not a merely wide-spread popular fancy, 

 anyone can satisfy himself if he trouble to watch the flocks of 

 sheep pasturing, for instance, on the south downs. The animals 

 when feeding move onwards 'from down to down in solid pha- 

 lanxes, the head of one sheep close by the head of its neighbour, 

 cropping closely the blades of grass whereon the snail with its 

 compactly formed shell lives and moves and has so much of 

 its being. 



