272 THE AGE OF MAMMALS 



Styria, and Germany; it stands remarkably near the living gibbon, and is 

 a smaller animal than either Oreopithecus or Dnjopithecus. The other form 

 from the Upper Miocene of Pikermi, Mesopithecus, is related in the abbre- 

 viation of its extremities, not to the tree-living, but to the true quadru- 

 pedal cynomorphs, or macaques; it is one of the earliest and most impor- 

 tant representatives of this branch. 



The Seven Rhinoceros Phyla of the Miocene 



The polyphyletic law is in no group more brilliantly illustrated than 

 among the rhinoceroses. The Miocene of Europe and North America opens 

 with the discovery of two phyla, both descended from Oligocene ancestors, 

 namely: (1) the pairhorned Diceratheriince, or diceratheres, (2) the hornless 

 AceratheriiruB, or aceratheres. To these are added in Miocene and Pliocene 

 times four more great phyla, namely: (3) the Teleocerince, or teleocerine 

 rhinoceroses, with a horn at the very tip of the nasal bones, with extremely 

 short feet and limbs, hence also known as brachypodine. There also ap- 

 pear in the Lower Miocene the first of (4) the Dicerorhince, also known as 

 the ceratorhine or Sumatran rhinoceroses, distinguished by two horns and 

 large cutting teeth, and destined to play a very important part in Europe 

 and survive in the existing Sumatran rhinoceroses; from these there branch 

 off in late Tertiary and early Quaternary times the Etruscan and broad- 

 nosed rhinoceroses, without cutting teeth. To these, at the summit of the 

 Miocene and again in the Pleistocene, are added (5) the Dicerince or atelo- 

 dine rhinoceroses, distinguished by two horns and the absence of cutting 

 teeth (hence atelodine), surviving in the existing African rhinoceros. 

 Then there appears, in the Pliocene of Asia only, the sixth great phylum 

 of (6) Rkinocerolinm, the typical or Asiatic rhinoceroses, with large, single, 

 anterior horns and jaws armed with anterior cutting teeth; these survive 

 in the existing Indian and Javan rhinoceros. A seventh phylum which 

 may have branched off from the aceratherine branch is that of the (7) 

 Ela smother id nxv, giant hypsodont forms distinguished by a single posterior 

 or median horn and known only in the Pleistocene of Europe and Asia. 

 These phyla in several instances divide into sub-phyla; for example, the 

 dicerorhine or Sumatran phylum, as noted above. The aceratherine phy- 

 lum sends off branches in some of which the skulls acquire minute horns 

 near the tips of the nasals. The dicerine, or African phylum, divides into 

 long-headed forms, now typified by the 'white rhinoceros,' D. simus, and 

 mesaticephalic forms, typified by the 'black rhinoceros,' D. hicornis. . 



1. Diceratheriinae, the diceratheres. 



2. Aceratheriinae, the aceratheres. 



3. Teleocerinae, the teleocerines or short-footed rhinoceroses. 



4. Dicerorhinae, the dicerorhine or Sumatran two-horned rhinoceroses. 



