V 
INTRODUCTION. 
Another objection will strike the mind of such 
as may seek their occupation or amusement in 
Hamming the more solid forms contained in the 
^tuseum. As the modem classification arranges 
close connection the Molluscs which may pos- 
sess or are deprived of, a testaceous covering, or 
in which the shells, taken alone, may appear of 
v ery different forms, a discordancy may appear 
' v hich shall seem far removed from our ideas ot 
fe lationship in nature. The natural affinities, 
liowever, are more dependant on the soft than 
*he solid portions, although unhappily the art 
n<ts not yet been found, of preserving the latter 
ln a state fit for examination. In some instances 
also, the shell alone is known to Naturalists: 
inhabitant never having fallen in the way of 
a n observer. But to obviate as much as possible 
all the difficulty likely to be thus encountered ; 
and more especially for the benefit of those who, 
deling an interest in the subject, may yet discover 
the philosophic arrangement to be rather an hin- 
drance than an assistance, an attempt is here 
'fiade to combine the spirit of the Linnean 
^thod with the arrangement of Lamarck, on 
Vv hich the work is founded. The manner of 
acquiring information may, and frequently ought 
to be, different from that in which it is retained ; 
and Mr. Bicheno (Trans. Lin. Soc. vol. J5,) has 
mown how well fitted in this respect an artificial 
Method is, to lead to the more easy and perfect 
aC( fuisition of the natural. 
It is with a view to this, that a rough outline of 
an arrangement is subjoined, by which it is hoped 
) e student will be assisted in Lis endeavour to 
discover the place of a shell, the scientific name 
which may be unknown to him. The dis- 
j 1 action of kindred species, however, can only 
be made, by reference to good figures, combined 
