280 HIGH SCHOOL ZOOLOGY. 



America in Miocene times and spi-ead thence to South Ameiica 

 and to Asia where they had not previously existed, but to which 

 the distribution of the modern form is limited. Again, the primi- 

 tive forms of the Tapir family lived in Europe during the early 

 part of the Eocene epoch, they spread during the later Eocene 

 and Miocene epochs to North America, where, however, they 

 died out without leaving any descendants, but they persisted in 

 Europe, where they gave rise to the modern Ta[)irs, and these 

 again spread to Asia and South America, where alone the 

 modern species occur. 



That Madasrascar was at one time connected with Africa, we 

 gather from the survival on the mainland of some of those pe. 

 uliar lemui'ine forms, which aie so characteristic of the Island. 

 But these have almost been exterminated from Africa by the 

 contact of the highei Eutheria, i-o that we conclude that the 

 connection with Africa was submerged before the influx of the 

 higher mammals from Eurasia. The persistence of the Proto- 

 theria and Metatheiia in Australia is similaily to be attributed 

 to its long independi nee from Asia. 



The fauna of Great Britain, finally, can only be accounted for 

 on the assumption that since the Glacial period it has been en- 

 tirely submerged, raised again, and populated from the main- 

 land, but again submerged before this repopulation could become 

 complete. The freedom of Ireland from reptiles is not to be 

 attributed to any uusuitability of climate, V)ut to the fact that 

 the channel was not dry land sufficiently long to allow these 

 forms, which are slow at distributing themselves, to reach it. 



1 6, Such facts lead us to the position that the geography of the 

 past has had the most important influence on determining the 

 geographical zoology of the present. Each species has a certain 

 area of distribution, which is called its habitat : it tends to 

 widen this area, as far as the conditions of existence will per- 



