An older Miocene form, mesohippus, has three toes in front, with a large splint-like rudiment representing the little finger, and three toes behind.
"The Old Riddle and the Newest Answer"
John Gerard
An older Miocene form, called mesohippus, has three toes in front, with a large splint-like rudiment representing the little finger; and three toes behind.
"Thomas Henry Huxley; A Sketch Of His Life And Work"
P. Chalmers Mitchell
Backward still, and the bones we find in the Miocene strata of the West, belonging to those ancestors of the horse to which the name of mesohippus has been given because they are midway in time and structure between the horse of the past and present, tell us that then all horses were small and that all had three toes on a foot, while the fore feet bore even the suggestion of a fourth toe.
"Animals of the Past"
Frederic A. Lucas