30 CLASS MOLLUSCA. 



from the Maldive Islands to Bengal, and from thence 

 sent into this country. The value of these shells as a 

 circulating medium depends naturally enough on their 

 greater or less abundance. 



In Bengal, in general, from 2000 to 2400 are equal in 

 alue to a shilling. But in Africa they are much dearer, 

 about 250 being valued at a shilling. 



The Cowrie shell is found of three different forms, 

 according to its age. First, in its extreme youth, when, 

 the shell is extremely imperfect, and is like a slender 

 'one, without any appearance of the usual characters of 

 the genus. Secondly, M'hen half grown ; it then begins 

 to assume the form of the perfect shell, but is extremely 

 slight, and colourless, and the point of its spire projects. 

 Thirdly, when perfect ; it has now received a second 

 deposit of shelly matter, in which its specific colours 

 appear, and its spire is completely hidden. The second 

 deposit with which the shell is covered, is secreted by 

 the two membranous wings of the creature's mantle, 

 which, in the adult state of the animal, have rapidly 

 increased and become extremely large, so much so, as 

 to be capable of covering the whole of the shell, while 

 the deposition of the new matter is taking place. 



Lamarck says the observations of the habits of this 

 creature tend to prove that, in addition to the power of 

 completing its shell, as we have already noticed, it can, 

 when its increased size has caused it to require a new 

 habitation, desert its former shell and form a new one ; 

 from this it happens that the same individual can form 

 successively many shells of different sizes, so that we 

 find the same species both large and small. 



When not in search of food, these animals are found 

 buried in the sand, at some distance from the sea-shore, 

 in temperate as well as in hot climates. 



