TEETIAEY PERIOD BY MEAXS OF THE MA1I3IALIA. 395 



16. The Development of Antlers in tlie Deer. 



The Pliocene deer occupied a position intermediate between those 

 of the preceding and succeeding ages in regard to their development 

 of antlers. In the Lower Miocene none of the Cervidoe were 

 an tiered. In the Mid Miocene the antlers bore simple forked 

 crowns ; and in the Upper Miocene the)- become more complex, but are 

 stiU small and erect, like those of the roe. In the Upper Pliocene 

 they are larger and longer, and altogether more complex than they 

 were before, some forms, such as the Cervus dicranios of Nesti, 

 being the most complicated antlers at present known. The deve- 

 lopment of antlers reaches a maximum in the Irish elk of the Pleis- 

 tocene and Prehistoric ages. These successive changes are like 

 those which take place in the development of the antlers in the 

 living deer, which begin with a simple point and increase in size 

 and in the number of tynes up to their limit of growth. It is 

 worthy of remark that in the Mid-Miocene strata of Thenay 

 small erect branching antlers, without a burr or rose and persistent 

 through life, represent an intermediate^form between the deer and 

 the antelopes. Similar antlers to these have been figured aud 

 described by Professors Leidy and Cope from the Upper Miocenes or 

 Lower Pliocenes of the United States. 



The Pliocene Mammalia of the Coralline, Eed, and Norwich Crags 

 are so imperfectly known, so fragmentary, and so mingled with 

 Miocene fossils while they were exposed to the dash of the waves on 

 the Pliocene shore, that it is better not to attempt to give a sys- 

 tematic list of those occurring in Britain. 



We come now to that period in the history of life when the 

 existing species of Mammalia preponderate greatly over the extinct, 

 to the Pleistocene age, in which the living species stand to the 

 extinct in the relation of fifty-six to twenty-two, out of a total of 

 seventy-eight. They fall naturally into three divisions, as I have 

 already pointed out in previous communications to the Society : — 

 the Early-Pleistocene, or that of the Forest-bed group ; the Mid- 

 Pleistocene, or that of the Brick-earths of the lower Thames ; and 

 the Late-Pleistocene, or those of most of the river- deposits and 

 most of the caves *. 



18. The Early -Pleistocene 2Iaramalla of Britain. 



The Earlj'-Pleistocene Mammalia from the Forest-bed of Norfolk 

 and Suffolk, given in tlie following list, are remarkable for the 

 association of Pliocene species with living and extinct species before 

 unknown. It will be remarked that the whole of the new living 

 species are now to be found in the temperate regions. 



* Quart. Journ. Geol. Soc. vol. xxyiii. p. 410, x^iii. p. 91. 



