. Irish Mammals. C>j 



the historic period. Of these tv/ent3^-six are Irish, but the 

 Wolf, the Brown Bear, and the Wild Boar are now extinct, 

 while the Black and Brown Rats, the Rabbit, the Fallow Deer, 

 and the Squirrel are introduced as doubtfully indigenous 

 species, so that our present list of truly indigenous Irish 

 mammals fairly includes only eighteen species, and in historic 

 times Ireland appears never to have had more than twenty- 

 one species. Great Britain, on the contrary, has been inhabi- 

 ted by about forty species, while the neighbouring parts of the 

 Continent of Europe possess many more. 



In discussing the cause for this difference in richness of the 

 fauna of countries lying so close to each other, Mr. I^ydekker 

 brings forward three theories— (i.) That of Dr. Wallace, who 

 attributes the disappearance of the ancient British Fauna to a 

 submergence of comparatively late date ; (ii.) that wdiich 

 attributes the disappearance of the greater part of the fauna to 

 the ice-sheet of the Glacial Epoch, and (iii.) that of Mr. G. W. 

 Bulman (expressed in a recent paper) that the ice-sheet did 

 not extend further south than the latitude of I^ondon, if as 

 far south as that, whence the fauna again spread northwards 

 with the return of more favourable conditions, although with 

 the loss of such forms as were unable to withstand a 

 considerable amount of cold. On this latter view it is 

 considered that Britain never was connected with the 

 Continent after the passing away of the Glacial Period. 

 On the two former views we must attribute our new fauna 

 to a short connection with the Continent subsequent to the 

 destruction by the ice of the Glacial Period. Of these theories, 

 Mr. lyydekker is more inclined to agree with the second — 

 indeed, Mr. Bulman's ingenious suggestion does not seem to 

 account for the poverty of the mami;iaiian fauna of Ireland as 

 compared wdth that of the rest of Britain. 



At this point we should have expected some attempt at an 

 explanation of the peculiarities of our Irish mammalian fauna, 

 but not a word have we on the subject, in fact the difficulty 

 has been ignored by Mr. lyydekker in a manner similar to 

 that in which he has ignored many others in his book. Not 

 even is there a reference (we believe, in the whole book) to 

 the work of the late Professor A. I^eith Adams, who wrote in 



^ Nalural Science^ Oct., 1S93. 



