xu 



INTKODUCTIOX. 



soraetliing of the inmate of such a dwelling. All nature proclaims 

 the goodness of God. AYe hear that the bird which wings its 

 way over our heads has a song of joy ; the bee hums dehghtedly 

 by us; and the little slirimp which darts in the clear pool, seems 

 full of merriment. AYas the inmate of the shell less cared for 

 by its ^Nfaker? !Xo doubt the little builder had some sense of 

 joy, as he framed from his own substance the house which excites 

 our admiration. Doubtless his existence, short and sluggish as 

 it was, had its own consciousness of pleasure; and obscure as is 

 his history, and little calculated as such a creature might seem 

 to perfonn an important part in the economy of creation, yet we 

 know that he had a work to do, not only for the living creatures 

 of the sea, but for the well-being of man himself." 



CLASSIFICATION OF SHELLS. 



The great naturalist Linna?us divided shells into thirty-six genera, 

 each of which comprised a number of species; of these species 

 somewhere al)out two thousand five hundred have been described and 

 classified; the varieties, more or less distinct, are almost countless. 

 Of shells found on and about the British Isles, there are about 

 five hundred and fifty species, or, we should rather say were, for 

 diligent enquirers into this branch of Natural History, are almost 

 daily adding to the number. 



"\Ve have already seen that shells are sometimes called Crystalline^ 

 and sometimes Granular, in accordance with certain peculiarities 

 of construction before mentioned: this is one mode of division; 

 there are several others made use of in different systems of 

 arrangement, which only a deeper study of the subject than can 

 be here entered upon, would enable one to understand; the plainest 

 and most common, however, is that which has reference to the 

 form of the shell, which is one of these — 



MULTIVALVE. 



Wliclk. 



Mussel. 



Barnacle. 



