PREFACE. Xill 



Sander Rang, Muller, and other eminent Malacozoologists. 

 For the arrangement I am indebted to these authors ; 

 but I have modified their views to suit my own notions, 

 as every one, I believe, does, on such occasions. The 

 synopses, specific descriptions and remarks, are entirely 

 original. 



The work being intended for the use of my pupils, and 

 for persons commencing the study of the Mollusca, I 

 have given a general account of the structure of those 

 animals, together with their classification, and the prin- 

 cipal characters of the classes and orders. Although 

 descriptive of the county of Aberdeen, with the adjoin- 

 ing portions of those of Banff and Kincardine, it will be 

 useful to persons residing in any part of Scotland, es- 

 pecially to those in the more northern districts. I pre- 

 sent it with confidence to the public ; because I am 

 conscious of having prepared it with great care, and be- 

 cause I think it will be useful. The specific descriptions 

 I have made fuller than usual, because I am anxious to 

 induce my pupils, not to content themselves merely with 

 learning the names of objects, as I have observed to be 

 the prevailing practice both here and elsewhere. It is, 

 in fact, a matter of no importance to an individual, by 

 what name an object is known to him, provided he be 

 acquainted with its structure and relations ; although a 

 fixed nomenclature is essential to the general progress of 

 knowledge. For this reason, I have not withheld the 

 various species, which have appeared to be new to 

 science, although the want of access to all the works 

 and essays published of late years, leaves it probable 

 that some of them have already been named. It is but 

 a pitiful manifestation of self-esteem to withhold the 

 knowledge of an object, lest it should ultimately be 

 found to have been already communicated in some work 

 inaccessible to the student. Besides, if I have ignorantly 

 given new names to objects already named, who of the 

 most successful cultivators of Zoology, has not often 

 committed similar errors ? 



In fine, such as it is, being the first Zoological work 



b 



