464 



THE OCEAN WORLD. 



Fig. 306. — Strombus luhuanus Fig. 307- — Strombuscan- Fig. 308. — Strombus thersites (Gray). 

 (Linnaeus). cellatus (Lamarck), 



Fig. 309. — Pteroceras scorpio 

 (Linnaeus). 



Fig. 310.— Pteroceras millepeda 

 (Linnaeus). 



from those of Strombus chiefly in this, that the right edge develops 

 itself with age into long and slender digital spines more or less 

 numerous, the numbers of which vary according to the species. The 





