INVERTEBRATE ANIMALS. 29 



Upper Compartment. 

 U Series of i3olisbed HaUotis, including the prin- 

 cipal kinds used in the manufacture of papier- 

 mache articles, card cases, &c. 



Family TKOCHID^. 

 Group 81.— Sub-Family ASTEALIIN^ and allies, a^rpov, 

 a star. Estimated number of species : recent, 200 ; 

 British, 3 ; fossil, 6. Miocene. 



H Examples of Stomatdla, Gena, Stella, Rotella, 

 Guilfordia, Brodcripia, Trochiscus, Camitia, 

 Microtis, Scissurella, &c., constituting an 

 assemblage of very beautiful generic forms. 



Group 82.— Sub-Family TROCHINiE. trochus, a hoop. 

 Estimated number of species: recent, 600; British, 16; 

 fossil, 300. Silurian, &c. 



The shells of the TrochincB are found on the 

 coasts of all seas, and exhibit a remarkable 

 variety of form and sculpture. 



Group 83.— Sub-Family TURBININ^ and allies, tnrho, 

 a top. Estimated number of species : recent, 110 ; 

 British, 1 ; fossil, 420 (?). Silurian, &c. 



H Specimens of Turho and Phasianella, shewing the 

 solid stony operculum characteristic of the group. 



Group 84.— Family NERITID^. vYiplrrig, the Sea-snail. 

 The species of Nerita are marine, those of Neritina 

 and Navicella inhabit fresh or brackish water. Esti- 

 mated number of species : recent, 350 ; British, 1 ; 

 fossil, 100. Oolite. 



^ Clitlwn longispina, distinguished by a remarkable 

 B 



