INVERTEBEATE ANIMALS. 31 



IT Amimllaria, Paludina, Paludomus, Bithynia, 

 Nematura, &c., all inhabitants of lakes or 

 rivers. 



Upper Compartment. 



Ampullaria gigas, from the River Amazon. 



Group 88.— Family LITTORINIDiE and allies. lithis, 

 the sea-shore. Periwinkles. Estimated number of 

 species : recent, 420 ; British, 60 ; fossil, 100. 

 Permian, &c. 



IT Liitorina, Rissoa, Planaxis, cC-c. Litiopa from 

 the Fnciis natans in the Sargasso Sea. 



Group 89.— Family MELANIID^. jasAac, black. 



Melania, Melanopsis, &c. Estimated number of species : 

 recent, 407 ; British, ; fossil, 72. Tertiary. 



H Illustrations of about 30 generic and sub-generic 

 forms, all from fresh water. 



Group 90. — Family CANCELLARIID^ and allies. 

 cancelli, lattice work. Estimated number of species : 

 recent, 274 ; British, 6 ; fossil, 720. Trias, &c. 



^ Trichotropis, Aporrhais, Cerithium, Struthi- 



olaria, Halia, Admete, &c. 

 Trichotropis hicarinata, and a fine series of 



Cancellaria. 

 The fossil representatives of this group are very 

 numerous, and are often found in the finest 

 possible condition. 



Group 91.— Family CYPR^ID^ and allies. Cowries. 

 Estimated number of species : recent, 200 ; British, 3 ; 

 fossil, 64. Cretaceous, &c. 



H Examples of Cyprcea, Trivia, Ovubim, Pedi- 



