15 
WEDNESDAY, MARCH 91, 1904. 
Ghe Gholution of the Borse. 
BY 
Dr. A. SMITH-WOODWARD, LL.D., F.R.S. 
(Keeper of the Department of Geology, British Museum.) 
p* SMITH-WOODWARD commenced by saying that the 
horse was a very satisfactory animal to deal with as regards 
tracing its evolution. In the early part of the Tertiary epoch, 
the ancestor, Phenacodus, was an animal about the size of a 
small collie dog, living mostly in water and in marshy districts, 
each of its feet five toed, widely spread to enable it to walk on 
soft ground, with a long tail to help it in swimming. The 
different stages were shown whereby the neck in the early animal, 
devoid of lateral movements, evolved into the flexible sinuous 
neck of the modern horse, capable of being turned quickly in 
every direction for self protection. The teeth, originally adapted 
for chewing succulent vegetable food only, had developed in 
course of time into the powerful grinders which the horse now 
possesses. The limbs, in early times able to execute a turning 
movement like the human arm, had settled down into ones 
adapted only for forward and backward movement, and were 
exquisitely contrived for rapid locomotion. With close detail 
and many diagrams, the Lecturer showed how the original five 
toes of the foot, adapted for soft ground, dwindled to three, and 
how the exterior tees of the three by disuse became less and less 
important and smaller in size, until they had shrunk into mere 
vestiges, leaving the central toe expanded and hardened into the 
hoof, so excellently adapted for galloping over hard ground. 
With regard to cloven-footed animals, two toes out of the five 
survived. No better example of adaptation of animals to 
changed conditions of life could be produced. 
Incidentally allusion was made to some of the monstrous 
ungainly forms that developed from the same _ ancestor 
Phenacodus, and pictures were cast on the screen of the probable 
appearance of the Tinoceras, Titanotherium, &c. Referring to 
the fantastic horns that adorned Tinoceras, Dr. Smith- Woodward 
