The Conch Shells 



mon. All tropical seas have their representatives. Yet the 

 largest, finest and most prolific species of the genus live in 

 the West Indies. 



THE SCORPION SHELLS. SPIDER SHELLS 

 Genus PTEROCERA, Lam. 



Shell spiral, oval, heavy, the outer lip prolonged into long 

 finger-like processes. Animal like Strombus. Ten species. 



Our American coasts have no representatives of this striking 

 group. They are sociable, shore-loving mollusks, closely allied 

 to Strombus. Where our genus exaggerates the outer lip into 

 an unnecessary wing, these species use an equal amount of material 

 in the long, curved fingers that make the mollusks look like great 

 spiders or scorpions, travelling upon six or eight legs. The young 

 have plain-lipped shells until quite well grown. Then the points 

 grow out as hollow canals containing filaments from the mantle 

 margin. Ultimately they become solid. The surface bears 

 strong knobs and ridges, and the smooth, polished aperture has 

 a pink or orange lining. Tropical seas of the eastern hemisphere. 



P. bryonia, Chemn.,from the Society Islands, is the largest 

 species. The description above just fits it. The specimens 

 approach a foot in length. Ponderous and coarse outside, the 

 wide aperture reveals an expanse of fawn-coloured enamel tinged 

 with pink that is truly beautiful. 



THE LITTLE BEAk SHELLS 

 Genus ROSTELLARIA, Lam. 



Shell spindle-shaped, with elevated spire of many smooth 

 whorls, the last prolonged into a slender anterior canal ; posterior 

 canal extends from the top of the aperture, outer lip thickened, 

 dilated, set with teeth; operculum not saw-toothed. Animals 

 similar to Strombus in structure and habits, though usually 

 timid and suspicious, whereas the conchs are bold. They inhabit 

 the China Sea, the Red Sea and the Philippine region, in deep 

 water. Tryon describes ten species. Type, R. curta, Sby. 



The comparative variability of certain of these shells has 



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