PREFACE. XI 



have dissented from the Linnaean school, 

 have, indeed, satisfactorily pointed out 

 some flaws in the great fabric of the 

 '* Systema Naturae ; " but in attempting to 

 eradicate the faulty parts, and to supply 

 their place more fitly, they have injured 

 some of the main supports, and have nearly 

 involved the whole edifice in ruin. 



The following pages are devoted to the 

 task of facilitating the study of conchology, 

 on the method of the Swedish naturalist ; 

 and they are written under the firm persua- 

 sion, that a material change is dangerous, 

 even in speculative matters, when the prin- 

 ciple has stood the test of general consent, 

 and when the means of reaching perfection 

 are not yet, and perhaps may never be, 

 attainable. 



