74 COLIN CLOUTS CALENDAR. 



islands, and the more so the smaller their area and the 

 more peculiar their climate. The intervening sea prevents 

 free reinforcement of the orifrjnal breed from the main- 

 land ; and so new varieties adapted to the special 

 circumstances soon establish themselves, and before lone 

 grow into distinct species. Even in so large an island 

 as Great Britain itself, but recently separated from the 

 Continent, we have already one peculiar native bird — the 

 Scotch grouse, which, as everybody knows, is not found 

 anywhere else in the world ; while we have several 

 native butterflies, as well as dozens and dozens of in- 

 cipient varieties, which may possibly establish them- 

 selves as species in the course of time. But in our 

 smaller outlying islands, with their equable temperature 

 and very insular character, including generally the 

 absence of many common enemies — such as birds of 

 prey, foxes, weasels, and so forth— numbers of separate 

 local species have been noted b>- Mr. Wallace and other 

 investigators. Thus, Shetland and the Isle of Wieht 

 have each a peculiar beetle of their own ; Man has a 

 dwarf butterfly and a tailless cat ; Guernsey has a caddis- 

 fly all to itself; and the Kerry Mountains (almost insular 

 in climate and abounding in peculiar plants of southern 

 type) have a water-snail. Almost every little island has 

 also numerous local varieties. These cases are quite 

 dificrent from that of the Steep Holm paiony, which is 

 merely a flower belonging to the great chain from the 

 Caucasus to the Pyrenees, reappearing in an isolated 

 spot in Britain ; whereas the peculiar island animals are 

 confined to these small areas, on which therefore they 

 have presumably been developed. Furthermore, lakes 

 are to the world of water what islands are to the world 



