32 
and now-a-days, when any incautious opponent ventures to ask, 
‘«¢ Where are the missing links?” the geological Horse is at once 
trotted out for inspection. 
The Lecturer then exhibited on the screen, and described some 
of the earlier forms of the Hoofed Animals; after which he went 
on to say :— , 
All our representations have been of animals belonging to the: 
same great Order as the Horse; but we have noticed a considerable 
amount of variation in the number of toes on each foot. The horse- 
has one, the Ox two, the Hipparion had three, but probably was. 
supported wholly by the middle one, the Rhinoceros had and still 
has three, the Hippopotamus four, while the Deer, Giraffe, Pig, &e. 
walk upon two. The number forms the most evident characteristic: 
to the ordinary observer. But the student detects something 
beyond this. He finds that the hoofed animals fall easily and 
naturally into two smaller groups, according as the weight of the 
body is supported on one or on two specially enlarged toes; these 
are (a) The Odd-toed (Prrissopacryza), (b) The Even-toed 
(Artiopacryxa), the type of the former being the Horse, of the 
latter, the Ox or Deer. The Paleontologist finds that this division 
holds good for all their past history, and it is evidently a natural 
division. The typical number of digits among the Mammalia 
would appear to be five, but this number at the present time is 
found only on those animals which use their limbs for purposes. 
other than support or locomotion ; e.g., the Mole and the Monkey. 
In early Tertiary times the number five was much more prevalent 
than it is now, and was as I said, probably normal. Among the: 
Ungulates the number apparently decreased gradually by disuse as. 
the necessity for them decreased. In those whose favourite habitat 
lies among soft or marshy ground, the decrease has gone on to a 
less extent because the spreading out of the toes and a large surface 
to the foot would be of advantage in giving them a surer footing. 
“ The toes” (of the Hippopotamus) says Sir 8. Baker “spread 
widely upon soft ground, and although not actually web-footed,. 
the skin between each toe expands to a certain degree, which 
assists the animal’s progress when swimming by offering a consider- 
able resistance to the water.” ; 
As the old surface land became better drained and drier, it was 
most advantageous to animals living upon such ground that the 
surface of the foot should lessen, and with it the number of digits, 
conferring on them thereby a higher rate of speed, a better chance 
of escape from their enemies. The group containing the Horse, 
which includes Ass, Zebra, and Quagga, has altered most of all, and 
there we find the highest rate of speed, the bones of the limbs 
having decreased and become more compact, and the whole body 
lighter. And as already said. this classification by the number of 
