MOLLUSCA OR UNIVALVES. 217 



oval, long, not wide ; lips disunited 

 at the upper part ; right lip sharp, 

 left smooth ; the last whorl much 

 larger than the others ; a shelly 

 operculum. Animal, head having 

 two long and round tentacula, with 

 eyes on two footstalks ; foot ob- 

 long. — 10 species recent, and 2 

 fossil. 



Some species are beautifully coloured, smooth, 

 and shining, and were formerly rare. The 

 greater number have no epidermis. They are 

 found in South America, India, New Holland, 

 the Mediterranean, &c. 



84. Turritella. — Shell very long, needle- 

 shaped, with numerous whorls, usually trans- 



versely striped; no umbilicus; mouth round; 

 lips disunited at the upper part ; the right lip 

 has a sinus or indentation about the centre. 

 Animal with two tentacula, long and very fine 



