CONCLUDING REMARKS. 



In the present state of our knowledge of the distribution 

 of the Mollusca in Scotland, it would answer no reason- 

 able purpose to institute a comparison between tliose of 

 our and of other districts. The Friths of Forth and 

 Clyde, with the adjacent land, the neighbourhood of 

 Berwick-ou-Tweed, and the Outer Hebrides, are, in so 

 far as T know, the only parts of the country that have 

 been subjected to a diligent search. The Aberdeenshire 

 district, forming a very natural zoological region, has 

 now, for the first time, been examined with reference to 

 its Mollusca ; but although it has been found to be more 

 productive thanitsnorth-easternsituation, granitic nature, 

 and exposed coast, could have led us to expect, a search 

 continued by an individual, .aided by his friends, for only 

 twenty-two months, cannot be supposed to exhaust so 

 wide a field. Very many species, no doubt, remain to 

 reward the zeal of future observers. 



Premature generalizations, and comparative lists drawn 

 up from imperfect researches, scarcely forward science, 

 but give rise to erroneous ideas ; as is well exemplified 

 by that portion of Mr. Forbes' s Report on the Distribution 

 of the British Pidmoniferous Mollusca, which refers to 

 our district, and which, however correct, according to 

 his knowledge, is inaccurate in fact. The species said 

 by him to occur in the ninth district of Britain, which 



