6o 



BRITISH MAMMALS 



• ist finger. 



- Prepollex. 



Talpa europaa. The Common Mole 



This animal is about 6|^ in. long, and of this length the 

 thick bristly tail occupies nearly \\ in. The body is almost 



cylindrical, and there is no clearly 

 defined neck. The front limbs are 

 remarkably modified. The elbow of 

 a mole's arm is contained within the 

 body, and the arm only protrudes 

 from the wrist joint. This and the 

 lower part of the arm are deflected 

 in such a way that the palm of the 

 hand is turned outwards and side- 

 ways. The bones of the hand are 

 remarkably expanded, and on the 

 inner or " thumb " side there is a 

 flattened bone that might well be 

 the prepollex,-' which looks, in fact, like a false thumb. The upper 

 arm bone, or humerus, is extraordinarily curved and shortened. 



The eyes in the Common Mole are not, 

 as is often supposed, absolutely non-existent. 

 It is thought, nevertheless, by the most 

 recent authority on the subject, Mr, Lionel 

 , E. Adams ^ (quoting also from Saint Hilaire 

 and Mr. Trevor-Battye) that an adult mole 

 is practically blind. Saint Hilaire, however, 

 thought it was extremely short-sighted. 

 There is no doubt that when the extremely 

 minute eye of the mole is exposed it has 



Hand of Mole. 



Right Foot of Mole. 



Mt is a moot point whether the first air-breathing vertebrate, which 

 grew by degrees from out of a fish into an amphibian and was the parent 

 form of all land vertebrates, was six-fingered or five-fingered. There is a 

 constantly recurring tendency, throughout mammals (at any rate), for a sixth 

 finger to make its appearance, preceding the thumb. This is termed the 

 prepollex. 



2 A Contribution to our Knowledge of the Mole (Manchester Literary and 

 Philosophical Society, 1902). 



