Mesohippus is Greek for middle horse. It had three toes and existed in the late Oligocene Epoch (37-26 million years ago). It was the size of a large goat and ate leaves and plains grasses. It lived in fields near thin copses of trees. It existed 35-40million years ago. Unlike its predecessor its legs were longer and now only had 3 legs on the front feet. It's teeth changed to incisors and molars and the gap where we now place the modern horses bit had formed. Its eyes were further apart (and back) than the Eohippus. It's speed had also increased to escape predators.
30 million years ago, Mesohippus, or 'Middle Horse', was as big as one of today's sheep, with longer legs. The middle toe was the beginning of the hoof.