6 THE CABINET OF SHELLS. 
The Phosphate of Lime constitutes the base of the shells of 
the Crustacea. They are slightly elastic ; furnished with 
joints ; the animals having the power of moving them at will. 
Among these are the Lobster, the Crab, the Limpet, &c. 
DHE eee AC A 
have not these peculiarities ; the base of these shells being 
Carbonate of Lime, they have no elasticity. Another impor- 
tant distinction is, the different appearances they assume. 
Some are calxy, having a dry, chalky appearance ; some have 
a transparent, superficial, shining covering, like enamel; and 
others are covered with a sort of cuticle or skin, under 
which the shell exists, mostly consisting of Pearl, or Mother-of 
Pearl. 
Among the enamelled or porcellaneous shells are the Tel- 
lena, the Donax, the Cypria, &c. 
Among the cuticulated shells are the Oyster, Muscle, Nau- 
tilus, some species of Haliotis, &c. 
THE ANIMALS, 
which inhabit the Testacea are the Doris, Triton, Ascidia, 
Tethys, Limazx, Spio, Amphitrite, Terebella, and Nereis. 
For a particular description of the animals, the shells, and 
other interesting matters relating thereto, the reader is referred 
to John Warren’s Book on Conchology, lately published in 
Boston. The curious, or those wishing to make collections, 
will receive much satisfaction by calling to see his Cabinet in 
Tremont-Street. It consists of an immense and beautiful col- 
lection of shells, with many rare and valuable Species. 
