UPON THfi BRITISH FLORA. 7 



zoological poverty in Ireland, which attains its maximum in 

 reptiles, as shown by the following figures : 



Belgium has 22 species of Reptiles and Amphibia. 

 Britain 13 ,, ,, 



Ireland 4 ,, ,, ,, 



There appear to have been two distinct migrations, one 

 from the north to Central Europe of the Reindeer, the Arctic 

 Hare, the Willow Grouse, &c., the other from the east through 

 Siberia. Both of them took place during the Glacial 

 period. American geologists recognize the existence of two 

 well-marked varieties of the Reindeer (Caribou), a small 

 one with rounded antlers, the other, which is larger, has 

 antlers more or less flattened. The eminent French palaeonto- 

 logist, M. Gervais, was the first to point out that the remains of 

 the Reindeer from the north of France differed from those found 

 in the south. His compatriot, M. Lartet, referred the southern 

 European remains to the Barren Ground Caribou, and those from 

 the deposits of Central Europe to the Siberian variety of the 

 present day, which he considered to be allied to the Woodland 

 Caribou of North America. Mr. Andrew Murray, in his work on 

 "The Geographical Distribution of Mammalia," reviews these 

 Reindeer and their claims to be regarded as varieties or species. 

 He speaks of the Lapland Reindeer as differing from the Siberian 

 in the character of the horns, which, in common with the two 

 American forms, he thought to be of one stock, modified by a 

 difference of climate, and conditions of existence. He points 

 out, too, that the difference between the Siberian and the Lapland 

 Reindeer consists in the greater length of horn and number of 

 tines, with a general disposition to palmation on the part of the 

 former. The two forms appear mixed in the British deposits. 

 The round-antlered form seems to have arrived in Europe long 

 before the other. Both probably came over by two different 

 routes. Dr. Murray speculates upon a former land communi- 

 cation between North America, Greenland, and Spitzbergen. 



