CH. xiii] D. GEOGRAPHICAL DISTRIBUTION 149 



Surname-distribution of farmers 

 in Canton Vaud {Switzerland) 



As a sequel to Guppy's study of surname-distribution of 

 farmers (who move about less than usual) in Britain, which 

 showed a good "hollow curve" by counties, the author has 

 studied Canton Vaud, which is about as large as Gloucestershire, 

 but much broken up into more or less isolated valleys by moun- 

 tains larger and smaller. Its nineteen "districts" average 64 

 square miles each, and they show as good a curve as, or even 

 better than, that of the English counties. A. very great number 

 of the villages, especially in the more rugged districts, contain 

 endemic names found nowhere else in the Canton. Not infre- 

 quently these occur on more than one farm, and then they 

 usually show a curve just like that of plants, with the greatest 

 number upon the smallest area (here one farm). The spread of 

 a name may be due to various causes that can hardly be regarded 

 as other than chance, as for example the chance that a farm may 

 fall into the possession of a woman of family X. If she marry 

 a man of family A, that family will rise in status by one farm, 

 and X may even be extinguished. The same process happens 

 with plants, and the plant (or the surname) that increases its 

 numbers increases its chance of spreading. The bulk of the 

 villages in the Canton have one or more names exceeding the 

 rest in number, and in general these names show greater dis- 

 persal in the Canton (just as the commoner plants in Ceylon, 

 for example, show greater dispersal outside the island). Spread 

 is alike in the two cases, so that it becomes very difficult to call 

 in adaptation or natural selection as the chief causal agent in 

 distribution. Rochat, for example, is the commonest name in the 

 valley of Joux, and has spread the most widely of the Joux names 

 in the Canton. But there is no adaptation, nor any handle for 

 natural selection, in the possession of Rochat as a name. No 

 shigle plant, and no single owner of a name, of course, can 

 become established anywhere without passing through the sieve 

 of natural selection, but that is its chief action. The effect of 

 selection upon a name, or upon a species, will be the sum of 

 its effects upon the individuals, and one must remember the 

 failures. 



Age and Area is very strongly indeed in favour of differentia- 

 tion. 



TEST CASE XXVII. CONTOUR MAPS 



It will commonly be found, in studying the distribution of the 

 species of a genus, especially if it be of small or moderate size, 

 that they are more densely congregated towards the centre of the 

 distribution of the genus, and fall off gradually towards the 



