CONUS CONE. 63 



of the surface. They are all natives of the 

 ocean, and are taken in the seas of hot climates 

 where they live at a depth of about ten or 

 twelve fathoms.* They are never found on our 

 coasts. Their name is derived from the Greek, 

 Kuvoq (conos) a cone. Now attend and answer 

 the questions I shall put to you upon all that I 

 have detailed. What kind of animal inhabits 

 the cone ? 



Child. It is one that breathes by means of 

 gills ; has a pair of tentacula bearing eyes ; and 

 its mouth is a long proboscis. 



Teacher. There is one part of the animal 

 which you have not noticed. 



Child. It has an operculum attached to its 

 foot, with which it closes the aperture of its shell. 



Teacher. What is remarkable in the habits 

 of this rnollusk ? 



Child. It is supposed to absorb the matter 

 of which the interior convolutions of its shell 

 are composed. 



Teacher. What then is the appearance of 

 the shell when cut in halves ? 



Child. The interior parts of the whorls are 

 thin, whilst the outer part of the shell is thick 

 and strong. 



Teacher. What advantage is the animal sup- 

 posed to derive from the external convolution 

 being so much thicker than those within the 

 shell ? 



Child. The thinness of the interior diminishes 

 * A Fathom is six feet. 



