436 



THE OCEAN WORLD. 



white spots, which is very common on the shores of the Medi- 

 terranean. 



The eighth family is Neritidcz, of which we may give as typical 

 genera, Neritina, Navicella, and Nerita. The species of Ncrita are 

 numerous and pretty, and are mostly marine. 



Fig. 231. Monodonta labia (Lamarck). 



Fig. 232. Delphinula sphserula (Kiener). 



The ninth family, Turbinida, has among its more important genera 

 those of Turbo, Phasianella, Trochus, Delphinula, and Imperator. Of 

 Delphinula only about seventy living species are known. They are 



Fig. 233. Imperator stella (Lamarck). 



Fig. 234. Trochus stellaris (Gmel). 



mostly natives of the Indian Ocean, and are remarkable for their 

 numerous spines and the asperity of their shells (Fig. 232). Of the 

 genus Imperator we may instance the Spurred Trochus, Imperator 

 stella, which is studded with radiating spines (Fig. 233), Imperator 

 stellaris (Fig. 234), they are natives of the Australian seas, and 

 Imperator imperialis, commonly called the Royal Spur. 



Our tenth family, Littorinida, contains the genera Solarium, 



