55 



Child. The difference in their general ap- 

 pearance, and in their mouth. 



Teacher. You have now formed a smaller 

 class. Such a subdivision is called a Genus, 

 from the latin word gen us, a kind ; the plural 

 of genus is genera. What have you done ? 



Child. Separated the shells that belong to 

 the same genus. 



Teacher. And to what two particulars, did 

 you attend in making your selection ? 



Child. To the general appearance of the 

 shell, and the form of the mouth. 



Teacher. The specimens which you have cho- 

 sen belong to the genus called Conus, the plural 

 of which is Coni. You must now examine the 

 shells carefully and try and discover in what res- 

 pect they resemble each other ; you will then be 

 able to describe their generic character, or mark 

 those qualities possessed in common by them all, 

 and which distinguish them from all other shells. 

 How will you set about this ? 



Child. We must compare them together, and 

 put down those qualities which they all possess. 



Teacher, First consider their general appear- 

 ance. 



Child. Their shape is very similar ; it resem- 

 bles a cone. 



Teacher. Yes, it is conical, and from hence 

 they have received their scientific name, Conus, 

 and their common English name, Cone. 



