MOLLUSCA OR UNIVALVES. 229 



longitudinally united ; right lip often wrinkled, 

 and left occasionally thickened ; operculum 

 horny. Animal like the Murex. 

 — 51 species recent, and 3 fossil. 



This genus is found in the 

 Mediterranean, Indian, and South 

 Seas: in many of the countries 

 near which it abounds it is used 

 as an instrument of music. By 

 breaking off the apex, or boring a 

 hole in it, and blowing through the 

 aperture, applied to the mouth of the performer, 

 notes can be produced ; and it is employed in 

 this manner by some rude nations as a military 

 horn. The Triton variegatum is often met with 

 fifteen inches, or even two feet, in length : it 

 is from the Asiatic seas, and is frequently beau- 

 tifully coloured. 



Family \2.—Pterida. % 



The shells of this family are frequently called 

 Wing-shells, from the circumstance of the last 

 whorl expanding more or less into the form of 

 a wing when the animal has attained maturity ; 



* Les Ailees, Lamarck. 

 Q 3 



