184' PECULIAR BRITISH BIRDS. [CH. IV 



these islands, which destroyed a large proportion of the 

 inhabitants, unable to escape to more southern and warmer 

 latitudes or, if they did, cut off from returning by the 

 severance of the land. Poor though the fauna is, there 

 are still a few species which are really peculiar to these 

 islands, and are not found, or at least have not as yet 

 been found, anywhere upon the Continent. As however 

 many of these supposed peculiar species are obscure and 

 small insects, it is quite within the bounds of possibility 

 that they remain to be discovered later upon the Continent, 

 Among the Vertebrata the peculiar species are mainly 

 fishes ; there are however three species of birds, or at 

 least forms that are reputed to be species, found nowhere 

 outside of the British isles ; the only one of these however 

 which is without any question at all a distinct form is the 

 grouse Lagopus scoticus. The Cole-tit Parus britannicus 

 is held by some naturalists to be distinct from the Parus 

 ater of the Continent ; and in the same way the 

 British form of the Long-tailed tit, called Parus rosea, is 

 distinguished from its ally in Europe. The St Kilda 

 wren is possibly also to be added to the list of peculiar 

 species. 



Mr Wallace enumerates no less than 15 different kinds 

 of fresh-water fishes which he states, on the authority of 

 Dr Gunther, to be well-marked species. They are entirely 

 Salmonoids and nearly all of them are lake fish ; they 

 include the familiar Gillaroo trout, the Loch Leven trout, 

 the Gwyniad, the Vendace and the Pollan. Considering 

 that in many cases these fishes are extremely restricted 

 in their range within the islands, it is not surprising that 



