THE REPTILIA, BATKACHIA, AND MAMMALIA 

 OF THE CHANNEL ISLANDS : 



THEIR ORIGIN AND MODIFICATION BY ISOLATION. 



BY J . SINE I. 



These three classes of the Channel Island fanna, though by 

 no means extensive, nor on a cursory review of much im])ort- 

 ance, afford none the less a very interesting study. As we 

 shall presently see, they ])resent and illustrate several 

 important points in the matter of geographical distribution, 

 and also, in a marked mannei-, show the effects of isolation ; 

 this last resulting in what may be either the conservation of 

 otherwise obsolete ancestral characters, or the evolution of new 

 ones. Some of these questions I shall attempt to deal with In 

 the pages which follow, but meanwhile I may mention one or 

 two points in illustration of my meaning. For instance : How 

 comes .lei'sey to possess a vole which is unrepresented either 

 on the neighbouring continent, in Great Britain, or even in the 

 other islands of the Channel Archipelago ? Again : Why 

 does Guernsey possess another vole, belonging to a separate 

 genus, which also is unrepresented elsewhere ? 



These questions are not easy to answer, but they are 

 receiving the attention of expert zoologists, and Mr. Bunting, 

 a naturalist on the staff of the British Museum, has recently 

 visited the islands for the purpose of procuring specimens for 

 the necessary study. 



A point in geographical distribution which I think has 

 not been previously noticed, and which is worthy of more than 

 passing interest, is the following. 



Taking it for granted, as is the consensus of opinion, 

 that such forms as we are here dealing with did not live in 

 these parts during the glacial period, but that we are indebted 

 for them to the East, South-east and South, it then becomes 

 noticeable that, with very few exceptions, those that were 

 unable to reach Guernsey owing to its having been previously 

 insulated, also failed to reach Ireland. 

 [1908.] 



