V1 PREFACE. 
first appearance.* The conclusion will not be found dis- 
figured by those gross typographical mistakes which per- 
vade the earlier portion, errors too numerous for the author 
to venture upon a list of “Errata.” A correct printer 
cannot be too highly appreciated by the writer upon natural 
science; the reputation of Linneus has suffered from the 
misprints of his synonymy. 
In the arrangement of the synonyms brevity alone was 
originally aimed at (such a reference as “ Ch. f. 399” was to 
simply imply that Chemnitz had there figured the same 
shell, not necessarily that he had similarly designated it), 
Lamarck’s names were usually placed first, and the vicious 
principle adopted of ascribing species, not to their first 
describer, but to the systematist who may have eventually 
located them in the modern genus. After page 289 the 
order of priority has been more attended to, and the 
references to such writers as Lister, Knorr and Argenville, 
who did not attach binomial epithets to their drawings, 
have been inserted in brackets. 
The author’s enlarged experience has enabled him, in- 
deed, to discern these and many other blemishes in his 
youthful work, but has, likewise, strengthened his con- 
viction of the great utility of the condensation, portability 
and suggestiveness which characterize it. The delicacy and 
minute fidelity of Wood’s engravings may, perchance, be 
equalled, but cannot be surpassed. 
* Plates 20 to 24, with their explanatory text, were published on 
the 26th of July last. 
