INVERTEBRATE ANIMALS. 33 



■ pttt^ CaW^ Case, 



The Mark f indicates specimens or other illustrations exhibited in the cases. 



Group 97. — Family CASSIDID^ and allies. cassis, a 

 helmet. Estimated number of species : recent, 80 ; 

 British, ; fossil, 50. Cretaceous. 



H Examples of Cassis, Dolium, Oniscia, Ficula, 

 (fc, including Morum exquisitum. 



Upper Compartment. 

 Cameos in various stages (rough medallions, half- 

 finished, and completed), from the shells of 

 C. Madagascarensis and C. rufa. Presented 

 by W. H. TooKE. Sections shewing interior 

 of shells. 



Group 98.— Family MARGINELLID^. inargo, a rim. 

 Estimated number of species : recent, 412 ; British, 1 ; 

 fossil, 50. Cretaceous, &c. 



11 Marginella, Erato, Columhella, Engina, 

 Many species of Marginella are unsurpassed by 

 any other shells in beauty of form and finish. 



Group 99.— Family MITRID^. mitres. Estimated 

 number of species: recent, 439; British, 0; fossil, 100. 

 Cretaceous, &c. 



% Illustrations of most of the 21 generic and sub- 

 generic forms constituting this extensive and 

 highly ornate family of shells, found chiefly 

 in the Philippine Archipelago. 



