56 LESSON X. 



Child. The name expresses very well the ap- 

 pearance of the genus. 



Teacher. It does ; but which is the broadest 

 part of a cone ? 



Child. The base. 



Teacher. And is the base the broadest part of 

 these shells ? 



Child. No ; quite the reverse. 



Teacher. They are therefore said to be in- 

 versely conical. What next do you observe ? 



Child. The cones are spiral. 



Teacher. Observe how the spire is formed. 



Child. By the whorls. 



Teacher. And how are the whorls arranged ? 



Child. They are spirally convoluted. 



Teacher. Compare the spires of the cones 

 with those of the other shells before you, and tell 

 me what you remark. 



Child. The whorls scarcely rise one above the 

 other. 



Teacher. You remember what a spire is called 

 when the whorls have the appearance of being 

 pushed into the body whorl. 



Child. Such a spire is called retuse. Here is 

 a Cone in which the upper whorls appear so 

 pushed into the body whorl that the spire forms 

 almost a flat surface. 



Teacher. What then is the character, of the 

 spire of the Cones. 



Child. The spire of the Cones is retuse. 



Teacher. Compare together all the different 



