A third great piece of palaeontological investigation with which the name of Huxley will always be associated, is the most familiar of all the instances taken from fossils in support of the evolution of animals.  This famous case is the pedigree of the horse.  In 1870, in an address delivered to the Geological Society of London, Huxley had shewn that there was a series of animals leading backwards from the modern horse to a more generalised creature called Anchitherium, and found in the rocks of the Miocene period.  He suggested that there were, no doubt, similar fossils leading still further backwards towards the common mammalian type of animal, with five fingers and five toes, and went the length of suggesting one or two fossils which might stand in the direct line of ancestry.  But in 1876 he visited America, and had the opportunity of consulting the marvellous series of fossils which Professor Marsh had collected from American Tertiary beds.  Professor Marsh allowed him the freest use of his materials and of his conclusions, and the credit of the final result is to be shared at least equally between Marsh and Huxley.  The final result was a demonstrative proof of the possible course of evolution of the horse, given in a lecture delivered by Huxley in New York on Sept. 22, 1876, and illustrated by drawings from specimens in Marsh’s collection.  The matter of the lecture has become so important a part of all descriptive writing on evolution, and the treatment is so characteristic of Huxley’s brilliant exposition, that it is worth while to make some rather long quotations from it.  The lecture was published in the New York papers, and afterwards with other matter formed a volume of American Addresses, published by Macmillan, in London.

“In most quadrupeds, as in ourselves, the forearm contains distinct bones called the radius and the ulna.  The corresponding region in the horse seems at first to possess but one bone.  Careful observation, however, enables us to distinguish in this bone a part which clearly answers to the upper end of the ulna.  This is closely united with the chief mass of the bone which represents the radius, and runs out into a slender shaft which may be traced for some distance downwards on the back of the radius, and then in most cases thins out and vanishes.  It takes still more trouble to make sure of what is nevertheless the fact, that a small part of the lower end of the bone of the horse’s forearm, which is only distinct in a very young foal, is really the lower extremity of the ulna.

      “What is commonly called the knee of a horse is its wrist.  The
     ‘cannon bone’ answers to the middle bone of the five metacarpal
     bones which support the palm of the hand in ourselves.  The
     ‘pastern,’ ‘coronary,’ and ‘coffin’ bones of veterinarians answer
     to the joints of our middle fingers, while the hoof is simply a
     greatly enlarged and thickened nail.  But, if what lies below the