54 LESSON VIII. 



Child, The beak is hollow. 



Teacher. It is; the interior is called the 

 canal, and the shells which have these beaks are 

 said to be canaliculaied ; and when the aperture 

 has not a beak or canal, it is called entire. 



Child. Is the beak of any use ? 



Teacher. Yes, the animals which have this 

 beak have an elongated tube, which is in some 

 way connected with their breathing. 



Child. Many of the shells have projections, 

 some like thorns, some ridges, and some rounded 

 protuberances. 



Teacher. The projections resembling thorns 

 are called spines, and the shells which have them 

 are said to be spinous. The rounded projec- 

 tions are termed tubercles, and the shells on 

 which they appear are called tuberculous. The 

 ribs, which are longitudinal rounded sutures 

 formed at the various growths of the shell, are 

 called varices, from the Latin varix, a swollen 

 vein. But such parts as occur only in a few 

 species we will notice when we examine the 

 species. You must now repeat to me the parts 

 of a univalve shell, and I will write them on the 

 slate. 



Parts of a univalve shell. 



The spire. The base, 

 whorls. aperture, 



body whorl. lips, 



first whorl. columellar lip. 



suture. outer lip. 



apex, columella. 



