30 INVERTEBRATE ANIMALS. 



Group 87. — Family AMPULLARIIDiE and allies, ampulla, 

 a globular vessel. Estimated number of species : 

 recent, 181 ; British, 6 ; fossil, 70. Tertiary. 



This family includes the so called Apple-snails, 



though differing widely from the true snails, 



which have lungs and are without opercula. 



H Ampullaria, Paludina, Paludomus, Bithynia, 



Nematura, dc, all inhabitants of lakes or 



rivers. 



Upper Compartment. 



Ampullaria glgas, from the River Amazon. 



Group 88.— Family LITTORINID^ and allies. littus, 

 the sea-shore. Periwinkles. Estimated number of 

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

 Permian, &c. 



H Littorina, Rissoa, Planaxis, dc. Lit'wpa from 

 the Fucus natans in the Sargasso Sea. 



Group 89.— Family MELANIID^. [j^sKug, black. 



Melania, Melanopsis, dc. Estimated number of species : 

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



^ Illustrations of about 30 generic and sub-generic 

 forms, all from fresh water. 



Group 90. — Family CANCELLARIID^ and allies. 

 cancelU, lattice work. Estimated number of species : 

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



M Trichotropis, Apori'hais, Cerithiuin, Striithi- 



olaria, Halia, Admete, dc. 

 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. 



