INTEODUCTION. 



Though we do not wish to add to the bulk of the 

 present little volume, we think a few explanatory 

 remarks needful to enable the young chonchologist, 

 to proceed easily in the pursuit of these interesting 

 objects of study. 



We have followed the nomenclature adopted by 

 Prof. E. Forbes and S. Hanley, in their msgnificent 

 work " British Mollusca/' the names there used being 

 those under which the species were first specifically 

 described. Those who are acquainted with this valu- 

 able work, will find in many places, we have adopted 

 the same observations, though somewhat condensed, 

 particularly as regards the external form and structure 

 of the animals, some of which we have not had the 

 opportunity of observing. On disputed points we 

 have generally taken the opinion of the most noted 

 conchologists, without entering into detail ; but, when- 

 ever practicable, and that has been almost always the 

 case, before adopting the remark of any author, we 

 have taken care that the same has been confirmed by 

 our own observations. 



With the expectation of this little compilation 

 falling principally into the hands of young persons, 

 or those just commencing the study of conchology in 

 this limited department, we have tried to adjust our 

 remarks to such ; we have been particularly careful to 



