EXPLANATION OF THE PLATES. 



Plate 1. 

 Chiton sqiiawosus. 



c. the scaly border. 

 Lcpas anatifera. 



n. tlie tentacula of the animal. 



b. the cartilaginous tube. 

 The four valves of the operculum 



of Lcpas Tintinnabulum. 

 Lepas irachewformh. 



Tintinnabulum, 



a. a. the outer valves. 

 b.b. the inner valves. 



c. the operculum. 



The under side of Lepas Dia- 

 dcma. 



A single valve of Pholas Dae- 

 tt/lus. 



jI. the cells at the back of the 

 hinge. 



The four accessory valves of 

 Pholas Dacti/lus. 



Pholas Dactj/h/s, with the acces- 

 sory valves in their places. 



One valve of Mj/a fruncaia. 



a. the hollow ofthe tooth where 



the cartilage is fixed. 



b. the truncated end. 



The two valves of 3Ii/a Vulsella. 



Plate 2. 



Mya pictorum. 



a. the hinge and teeth. 

 Solen Vagina. 



a. the cartilage. 

 Solen sanguinolentus. 

 Tellina cornea. 



a. the hinge and teeth. 



16. Tellina diroaricata. 

 17. radiatu. 



18. The two valves of Tellina inccqui- 



valvis. 



19. Cardium Uncdo. 



20. Mactra lutraria. 



a. the hollow where the carti- 



lage is fixed. 



b. the diverging tooth. 



21. Mactra stultorum. 



22. Donax Irus. 

 23. cuneala. 



24. Venus divaricata. 



25. " verrucosa? 



Plate 3. 



26. Venus Meretrix. 



a. the base. 



b. the upper margin. 



c. the anterior margin. 



d. the posterior margin. 



27. Venus imbricata ? 

 28. dejlorata. 



29. Spondi/lus Gaderopus. 



a. the area or triangular space 

 between the hinge and the 

 beak. 



30. Spondylus j)licatus. 



31. Chama Gigas. 



32. Hippopiis. 



33. antiquata. 



34. One valve of Chama Cor. 



35. Chama Lazarus. 



36. The two valves oi Area Nucleus. 



