3880 GEOGRAPHICAL DISTRIBUTION. 
. the general distribution of the family it is found that a 
greater or lesser number of allied species are confined to 
special regions, some species restricted to very small areas, 
and even to special localities, 
From the above it will be readily seen that it becomes 
difficult to draw up any statement of the number of species 
peculiar to different countries or regions. 
This subject has, however, been fully gone into by Mr. 
Baker, who, in an elaborate memoir of 47 pages quarto,* 
shows the general distribution of the order through the 
different zones and regions, and the relation of the species 
of the regions to one another ; the data which he has 
adopted are the localities given in the “Species” and 
“Synopsis Filicum,” the number of species recorded being 
2228, which are arranged and tabulated in a form showing 
the regions and countries where each species is found, and 
the species peculiar to each region. He divides the earth 
into four zones, namely, Arctic zone, North temperate zone, 
South temperate zone, and Torrid zone. These are sub- 
divided into ten regions, of which the following is a sum- 
mary, showing the total number of species, and also those ` 
peculiar to each region. 
Arcric ZONE. SZ 
1. Arctic zone or region. This region contains 26 
species, none of which are peculiar to it, all being - Se 
found in the adjoining zone. 
Norra Temperate ZONE. 
This zone is divided into three regions, as follows :— 
bo 
includes Europe and the whole length of North ` ` 
* “Linnean Transactions,” vol. 26, 1867. - ` 2 Se - 
. Temperate Europe and North Africa. This region ` 
