8 INTRODUCTION. 
ill-fated son of Linneeus, which is identical, or nearly so, with 
the manuscript of Solander, the esteemed conchological pupil 
of the great master. It is serviceable, chiefly, from containing 
a plain transcription of the manuscript remarks in the copy 
just mentioned; for his father’s writing, always crabbed, is at 
times perfectly illegible, from the porous nature of the paper 
he wrote on. The opinions, too, of one who had inspected the 
collection in its pristine and more perfect condition, are not 
undeserving of consideration. The acquisition by the Linnean 
Society of the books habitually used and quoted by the great 
systematist, to the engravings in which are attached, in his own 
handwriting, the names by which he has designated the deline- 
ated shells, has at times proved useful in correcting the typo- 
eraphical errors of citation which disfigure the pages of. his 
various productions. 
The works of all who have paid attention to the elucidation 
of the Linnean species have been sedulously consulted; and 
the author, whilst proceeding by a different and independent 
path of inquiry, has felt gratified on so frequently arriving at 
similar conclusions, both manuscript and specimens being al- 
most invariably confirmatory of those careful inductions which 
had taken place without access to either. 
As naturalists of even the highest capacity differ greatly in 
their views of the extent of variation permitted to each species, 
and the increasing fabrication of new genera for the smaller 
sroupings threatens to render the Lamarckian system as obso- 
lete as the Linnean, I have endeavoured to further illustrate 
my meaning by unchanging figures rather than by fleeting 
names. Great pains, indeed, have been bestowed in selecting 
those illustrative engravings which most resembled the actual 
specimens: hence the risk is avoided of naturalists being mis- 
led through any possible ignorance on my part of the modern 
names of species, —a fault, however, guarded against, I trust, 
by my undivided study of the Testacea for a long period of 
years, my examination of nearly all the public Museums of. 
Europe, and a correspondence or acquaintance with the majority 
of the more eminent living writers upon the subject. 
The long delay in the appearance of this work (which was all 
but completed five years ago), and the free communication of 
the results of my studies to my brother naturalists, has, I fear, 
