142 



DESCRIPTION OF THE PLATES. 



FIG. PAGE 



9. Limax agrestis 128 



10. Limax maximus 127 



11. Limax maximus, var 127 



12. Cutting tooth of Limax 

 maximus 127 



13. Limax ater ? young 129 



Plate XXVn. 

 Pisidium obliquum, animal. 131 

 Pisidium obliquum, exhibit- 

 ing the situation occupied 



by the young 131 



Cyclas cornea 131 



Cyclas cornea, shewing the 

 young in the parent shell ,. 131 



FIO. 



5. 



10. 



Dreissina polymorpha, ani- 

 mal 129 



a the byssus, b the lower 

 syphon, c the upper syphon. 

 The lower syphon of Dreis- 

 sina polymorpha, magnified 1 29 

 Unio pictorum, animal 130 



a the upper syphon, h the 

 lower syphon, c the foot. 

 Spawn of Unio pictorum... 130 

 Anodon Cygnea, animal ... 130 



a the upper syphon, b the 

 lower syphon, c the foot. 

 The lower syphon of Ano- 

 don Cygnea, magnified .... 130 



