Why horses should be found in Europe, Asia, and Africa, and not in
America, is not obvious; the explanation that the conditions of life in
America are unfavourable to their existence, and that, therefore, they
had not been created there, evidently does not apply; for when the
invading Spaniards, or our own yeomen farmers, conveyed horses to these
countries for their own use, they were found to thrive well and multiply
very rapidly; and many are even now running wild in those countries, and
in a perfectly natural condition. Now, suppose we were to do for every
animal what we have here done for the Horse,--that is, to mark off and
distinguish the particular district or region to which each belonged;
and supposing we tabulated all these results, that would be called the
Geographical Distribution of animals, while a corresponding study of
plants would yield as a result the Geographical Distribution of plants.

I pass on from that now, as I merely wished to explain to you what I
meant by the use of the term 'Geographical Distribution.' As I said,
there is another aspect, and a much more important one, and that is, the
relations of the various animals to one another. The Horse is a very
well-defined matter-of-fact sort of animal, and we are all pretty
familiar with its structure. I dare say it may have struck you, that it
resembles very much no other member of the animal kingdom, except
perhaps the Zebra or the Ass. But let me ask you to look along these
diagrams. Here is the skeleton of the Horse, and here the skeleton of
the Dog. You will notice that we have in the Horse a skull, a backbone
and ribs, shoulder-blades and haunch-bones. In the fore-limb, one upper
arm-bone, two fore arm-bones, wrist-bones (wrongly called knee), and
middle hand-bones, ending in the three bones of a finger, the last of
which is sheathed in the horny hoof of the fore-foot: in the hind-limb,
one thigh-bone, two leg-bones, anklebones, and middle foot-bones, ending