preface:. xiii 



Sander Rang, Muller, and other eminent Malacozoologists. 

 For tlie arrangement I am indebted to these authors ; 

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

 as every one, I beheve, 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 1 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 w^orks 

 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 



