Plate V. 



Vol. IV. 



<o 



10 



13 



Helix ericetoriim. 1, Pair of dart-sacs x 3. 2, Darts x 4. 3, Head 

 enlai-ged. 4, Section of base of dart-sac. 5, Darts in position. 



Helix caperata. 6, Dart-sac x 4. 7, Other side of same. 8, Dart x 6 

 Helix pisana. 9, Dart-sac x 2. 10, Dart x 10. 11, Mid-section of 

 dart. 12, Immature dart. 13-14, Heads of darts enlarged. 15, Section of 

 last. 16, Base of dart enlarged. 



