60 LESSON X. 



Child. No : there are stripes at the base of 

 some of them. 



Teacher. These are called strice, the Latin 

 for stripes. Are they only perceptible to your 

 sight ? 



Child. I can feel them also. 



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 stria, 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 

 str'uE. 



Teacher. Remember that the stripes are only 

 occasional, not invariable. Do you think that 

 any quality in these shells has escaped your 

 observation ? 



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 



