PRO. CONCH. SOC. GREAT BRITAIN AND IRELAND. 



151 



Spring Dyke, 1880. Odontophore. 



Beverley, 1880. Jaw. 

 Palate. 



X Jaws and odontophore. 



Odontophore. 



Beverley, 



Beverley, 1880. Jaws and odontophores. 



LimncEa stagnalis. 



L. 



L. palustris. 



Planorbis corneus. 



Neritina fiuviatilis. 



Ancyliis lacustris. 



Arion ater. 



Limax agrestis. ,, ,, 



Succinea p2itris. „ ,, 



5". elegans. Pighill Lane, Beverley. 



Helix aspersa. Beverley, 1880. 



H. caperata. ,, „ 



H. hispida. „ ,, 



H. rufescens. ,, „ 



H. virgata. „ „ 



H. arbustorum. 



H. cantiana. ,, ,, 



H. hortensis. „ ,, 



Pupa unibilicata. Walkington, 1880. 



Littorina litorea. 



L. obtusata. 



Mr. Butterell's letter drew attention to the jaws of Livincea 

 stagnalis and Planorbis corneus. It was seen that in L. stag7ialis 

 the side pieces hanging from the jaw are covered with filaments, 

 and the question arises in the mind whether these are intended 

 to prevent too large pieces entering the mouth or to retain what is 

 there — in fact, to act somewhat in the manner of the whalebone 

 in a whale's mouth, i.e., as a strainer. In the action of eating, 

 the odontophore moves up to the jaw and the hanging side pieces 

 close in both sides. Mr. Butterell's letter closed by asking for 

 informations from the members, as he has not seen the subject 

 treated in any of our books. 



Palate. 

 Odontophore. 



