FKESH-WATEE SHELLS. 3 



having a spiral turn or twist are called snail shells, and are 

 to be studied iirst. 



3. Let the pupils pick out from their collections the 

 sheUs like these : 



Fig. 8.— rBESH-WATEK Snaii-Shells. 



The difEerent spiral turns, or twists, are called whorls, 

 and the whorls together form the spire. The opening into 

 the shell is called the aperture, and the line separating the 

 whorls is called the suinire. The pointed end of the spire is 

 called the apex. 



> wAorla forming the spire. 



body-wTiorl. 



Fia. 4. — Shell, with Pakts named. 



