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[ The absence of any keel on the breast-bone and some other osteological peculiarities, observed by Professor Marsh, however, suggest that Hesperornis may be a modification of a less specialised group of birds than that to which these existing aquatic birds belong.]

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[ A second specimen, discovered in 1877, and at present in the Berlin museum, shows an excellently preserved skull with teeth; and three digits, all terminated by claws, in the fore limb. 1893.]

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[ I use the word "type" because it is highly probable that many forms of Anchitherium-like and Hipparion-like animals existed in the Miocene and Pliocene epochs, just as many species of the horse tribe exist now, and it is highly improbable that the particular species of Anchitherium or Hipparion, which happen to have been discovered, should be precisely those which have formed part of the direct line of the horse's pedigree.]

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[ Since this lecture was delivered, Professor Marsh has discovered a new genus of equine mammals (Eohippus) from the lowest Eocene deposits of the West, which corresponds very nearly to this description.—American Journal of Science, November, 1876.]