X 
PREFACE* 
two drachms of gum arabic or gum mastich, dis¬ 
solved in two ounces of spirits of wine, will make 
a light transparent varnish, easily to be washed 
off. And to remove the outer coat of theTrochi, 
or such as it may be the wish to preserve in ail 
uncoated state, the muriatic acid, diluted with 
water according to the strength of the shell, may 
be used 3 and afterwards to give the highest lustre, 
the manual operation of rubbing with pumice 
stone, tripoli, or rotten-stone. Specimens should 
also be collected in their different stages of growth ; 
for the young of many shells have so different an 
appearance from their full-grown state, as to be 
often mistaken for distinct species. 
i he more minute ones, as soon as they are 
ascertained, may be fixed by gum water on black 
or white cards, according to‘the opposition of their 
colors, labelled with their generic and specific 
names, and their exact habitats, with the addition 
of v. or 772 . to signify whether they have been pro¬ 
cured in a living or a dead state. 
It has also been our habit to place a mark in 
the margin of the descriptive work we generally 
use, against the species as it first occurred to us, 
by which, at one view, we distinguish such as we 
possess, and such as are among our desiderata. 
CONCHO- 
