18 



POPULAR CONCHOLOGY. 



some are supposed to live but one year or season, others 

 two, as the land snail. Again, others exist many years ; 

 and probably the ridges on the surface of many genera are 

 the terminations of the yearly growth ; but these are 

 scarcely more than suppositions. Many of the bivalves 

 attain their full growth in a year ; the oyster in four or 

 five. The Tridacna, and others of large size, must enjoy 

 unusual longevity.* 



Having thus given an outline of the nature of Mollusca, 

 or, in other words, of shells and their inhabitants) in order 

 that a general idea may be formed of them, their classi- 

 fication and arrangement into different orders and genera 

 may now be entered upon, so that the reader may have the 

 power of becoming more particularly acquainted with 

 them, and be able to decide upon the nature, habits, and 

 peculiarities of any shell, and the mollusc which has resided 

 in it, by a simple inspection of its form and appearance. 

 It is rarely indeed that the animal is to be met with in 

 collections, the shell only being retained as an object 

 worthy of preservation. 



The greater advance the reader makes in the study of 

 Conchology, the more the interest and delight will in- 

 crease. The beauty of form in some shells, the grotesque 

 shapes of others, the exquisite colouring and marking of 

 many, and the habits and peculiarities of the inhabitants of 

 all, will excite wonder and admiration at the care which 

 has been bestowed on creatures, of which thousands are 

 never seen by the eye of man. The reflection will arise 

 that they Avere formed by Him who has made nothing in 

 vain, and that these, among the many exquisite productions 

 of Nature, were created 44 for man to gaze on, wonder, 

 and adore." 



It will be advisable to give representations of a few dif- 

 * Woodward*s Recent ami Fossil Shells. 



