Pk t t V IL 



Vol. TV. 



^ ^/ 



Helix nemoralis L. — i, Dart-sac and mucous glands, nat. size. 2, Another 

 example. 3, Dart in position enlarged. 4, Dart. 5, Base of dart more 

 enlarged. 6, Immature dart, x 7. 



Helix ho7-tensis Mlill. — 7, Dart-sac, etc., nat. size. 8, One mucous gland of 

 another example. 9, Dart. 10, Base of dart more enlarged. \oa, Flanged 

 edge of blade cut transversely. 11, Immature dart, x 12. 



Helix ficsca Mont, — 12, Bilobed dart-sac, x 4. 13, Dart, x 15. 14, Verti- 

 cillate arrangement of mucous glands, X 10. 15, Dart in position. 



