CONUS CONE. 63 







Teacher. What kind of striae must they be if 

 you can perceive them by your touch ? 



Child. They must be raised. 



Teacher. Yes ; they are slightly raised like 

 wrinkles, on which account they are called 

 rugose strice, from the Latin rug a, a wrinkle. 

 What direction do they take ? 



Child. An oblique direction. 



Teacher. The columellar lip is nevertheless 

 called smooth, because it has but trifling eleva- 

 tions. How would you describe the columellar 

 lip of a cone ? 



Child. The columellar lip of a cone is smooth, 

 except that it is marked by a few oblique rugose 

 strict. 



Teacher. Remember that the stripes are only 

 occasional, not invariable. Do you think that 

 any quality in these shells has escaped your ob- 

 servation ? 



Child. They are all prettily marked, and have 

 a beautiful polish. 



Teacher. True; but the colours of shells 

 and the peculiarities on their surfaces are not 

 spoken of in the generic character ; these form 

 the distinctions of the different species. We 

 will now sum up what has been said respecting 

 the cones, and thus draw out their generic cha- 

 racter. You must first mention to which of the 

 three great classes they belong ; next their ge- 

 neral appearance ; and lastly, the form and pe- 

 culiarities in the aperture. 



