MOLLUSCA. 33 



Child. It seems very wonderful that so 

 many shells should have the same pattern. 



Teacher. It is indeed most wonderful. I can 

 telly ou however how it is supposed to be effected. 

 The pores containing the colouring matter are 

 arranged in the skin of the mollusca with the 

 same undeviating regularity as the spots upon 

 the leopard, or the stripes upon the tiger, and 

 when the liquid exudes, it stains the shell, and 

 the uniformity of the pattern is the consequence 

 of the order in which the pores are placed in the 

 mantle. Now look at all these shells, and con- 

 sider them only in reference to their colours and 

 markings. 



Child. The colours in some are very beau- 

 tiful, and there is great variety of patterns. 



Teacher. This is very true ; but are they all 

 different ? 



Child. No, there are some that have quite 

 the same pattern. 



Teacher. Then you may observe two points, 

 especially with regard to the markings ; what 

 are they 1 



Child. That there is a very great variety, 

 and yet some are alike. 



Teacher. Yes, a variety and uniformity most 

 wonderful ; but do you suppose that their being 

 alike is accidental ? 



Child. Oh no, it could not have arisen from 

 chance. 



Teacher. Very true, nor can we fail to ob- 

 serve, that however great the variety may be in 

 individual specimens, all the works of creation 



