ZOOLOGY. 



THE MOLLUSCA OF THE NORTH-EAST OF SCOTLAND/ 



~pO draw up and publish lists of the animals and plants of 

 A their own districts, should be one of the principal objects 

 of all local natural history societies; and the Aberdeen Society by 

 the publication of a catalogue of the Molluscaof the north-eastern 

 counties has shown that it understands what its work is. That 

 this list is sufficiently exhaustive may be judged from the fact 

 that out of 686 species recorded as natives of Britain and the 

 adjacent seas, 374 are included in the catalogue now before us. 

 Of these 71 are land and fresh-water shells, being only 7 less 

 than the number (78) known as natives of Scotland. We notice, 

 however, that of 5 of these 7 1 species no recent captures appear 

 to have been made, but that of 4 other species only one or two 

 specimens of doubtful origin (possibly, as is suggested, intro- 

 duced with ballast) have been found. Mr. Dawson has never- 

 theless thought proper to include these species in case they 

 should hereafter be found alive. 



In his introductory remarks the author describes the depth of 

 the sea, and the structure of the sea-bottom adjacent to the 

 north-east coast : mentioning where, and what species of, fossil 

 shells are found in it, and giving his opinion as to the various 

 geological changes, to the action of which the present structure 

 of the sea-bottom is due. 



" Towards the close of the glacial period and during the second condition,, when 



* ' ' Catalogue of the Mollusca of the counties of Aberdeen, Banff, and Moray, 

 and of the neighbouring seas. " A Paper comunicated to the Aberdeen Natural 

 History Society, by R. Dawson, A.M., Cruden. Printed for the Society. 



