TAYLOR: IXJMINANCY IN NATURE. 
21 
In the Mammalia, although the destruction or retreat to less 
civilized regions of those animals useful to man or deleterious to his 
interests has interfered so largely with their geographical distribution, 
yet exactly the same principles prevail as in other life groups. 
The Protjotheria stand at the very base of the mammalian series, 
and approximate in their structure and physiology to reptilian life 
standing between the typical warm-blooded homseothermic life and 
the cold-blooded poikilothermic reptiles. This group includes the 
Ornithor'hynchm and the Echidyiidce , the former conhned to Australia 
and Tasmania, and the latter ranging as fai as New Guinea, regions 
where all the most primitive life of the world is to a large extent now 
congregated and restricted. 
The Eutheria, of which the Marsupials are the most primitive 
representatives, lived in Europe in Mesozoic times and lingered there 
until the tertiary period, but their metropolis is now in Australia 
where they are the dominant mammals or were until the artificial 
introduction of the stronger and more modern forms ; representative 
species or genera also still survive in primitive South America and 
Eastern North America, but all are dwindling to extinction. 
The Wild Horse {Equas atballus przemlskii and celticus), though 
now restricted in the wild state to the deserts of Central Asia is 
probably the main ancestral stock of the ordinary domestic horses of 
North-west Europe, from which it differs in the shape of the skull, 
and the presence of distinct callosities on the fore legs only. 
In their geographical distribution they harmonize with the general 
laws and though now expelled in the truly feral state from Europe, 
they still survive in a wild and semi-wild state or in captivity on its 
outer fringe or in the immediately adjacent countries. 
In Iceland, the Faroes, the Shetlands, the Hebrides, the West of 
Ireland, the West of Norway and no doubt in other places, more or 
less closely related forms are found. It is also reported from North 
Africa, and is found in the wild state in the Gobi desert of Central 
Asia and quite recently inhabited the Kirghiz Steppes of Tartary. 
It also exists in a somewhat modified but domesticated state in 
Alsace, probably descended from the wild horses of the Swiss lake- 
dwellings period at which time they would probably be widely 
diffused over Europe, as the pre-historic sketches found in the 
Madelaine Cave, Dordogne, France, and the fossil skulls from the 
superficial deposits of Essex, show an animal quite similar to the 
present day Mongolian wild Horse. 
In Ornitholog'y we have an exemplification of the same principles 
or laws as in other groups, and perhaps the first generally accepted 
division of the earth into geographical regions was that devised by 
Dr. Sclater for the Passerine birds, which regions are still very 
generally accepted as most expressive of the distribution of life. 
Prof. Alfred Newton, the greatest scientific ornithologist of his 
day, was, apparently, quite in accord with the principles here 
