. Darwin, and after Darwin. An exposition of the Darwinian theory and a discussion of post-Darwinian questions. Evolution; Heredity. Palceontology. 167 restricted to the Ruminants, and appear under three different forms or types - namely,soHd, as in antelopes ; hollow, as in sheep ; and deciduous, as in deer. Now, in each of these divisions we have a tolerably complete palseontological history of the evolution of horns. The early ruminants were altogether hornless (Fig. 60).. Fig. 60.—Skull of Oreodon Culherlsoni. (After Leidy.) Then, in the middle Miocene, the first antelopes ap- peared with
. Darwin, and after Darwin. An exposition of the Darwinian theory and a discussion of post-Darwinian questions. Evolution; Heredity. Palceontology. 167 restricted to the Ruminants, and appear under three different forms or types - namely,soHd, as in antelopes ; hollow, as in sheep ; and deciduous, as in deer. Now, in each of these divisions we have a tolerably complete palseontological history of the evolution of horns. The early ruminants were altogether hornless (Fig. 60).. Fig. 60.—Skull of Oreodon Culherlsoni. (After Leidy.) Then, in the middle Miocene, the first antelopes ap- peared with tiny horns which progressively increased in size among the ever-multiplying species of antelopes until the present day. But it is in the deer tribe that we meet with even better evidence touching the pro- gressive evolution of horns ; because here not only size, but shape, is concerned. For deer's horns, or antlers, are arborescent; and hence in their case we have an opportunity of reading the history, not only of a progressive growth in size, but also of an increasing development of form. Among the older members of the tribe, in the lower Miocene, there are no horns at. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Romanes, George John, 1848-1894. Chicago The Open Court Pub. Co
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