CO LESSON X. 



Teacher. These are called stria, the Latin 

 for stripes. Are they perceptible to any other 

 sense than sight ? 



Child. Yes : I can feel them. 



Teacher. What kind of striae must they be, 

 if you can perceive them by your touch ? 



Child. They must be raised. 



Teacher. 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 

 strice. 



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 

 spoken of in the generic character are in general 

 the peculiarities on their surface ; these constitute 

 the distinctions of the different species. W T e 

 will now sum up what has been said respecting 

 the Cones, and by so doing we shall draw out 



