17 24. 



52 GUIDE TO THE FOSSIL MA1\IMALS AND BIRDS. 



Table-case |])q pr^^jp jj^ j^]] XJngulata with similar feet liviiitj; in tlie 

 iiuitlieru liemispliere. Some of tlie small Proterotheriidae, 

 which are found in tlie Santa Cruz Formation (perhaps 

 Pliocene) of Patagonia, have the toes reduced to one on each 

 loot, exactly as in the horses; hut here again the ulna and 

 iil)ida are complete. They arc named Litopterna (" smooth 

 heel ") because the calcaneum is provided with a smooth 

 facette for articulation with the end of the fibula. In 

 outward appearance they must have been much like pigmy 

 horses. 



Sub-order 11. — Proboscidea. 



^|ll-cases Tiig elephants at the present day are found only in Africa 

 Pier-cases ^^^^ ^^^^ Indian region, Ijut during the Pleistocene period they 

 29-42. ranged over nearly the whole of the northern hemisphere, 

 Table-cases roaming even within the Arctic circle. The mammoth 

 {Elcphas 2Jrimigenivs), which was almost identical with the 

 living Indian elephant, had the widest distribution, its 

 remains being especially abundant in the frozen Arctic 

 lands and occurring almost everywliere in the north temperate 

 region. There were local variations of the species ; and 

 among other features it may be noticed that the grinding 

 teeth from the north exhibit finer and closer triturating 

 plates than do those from the south, both in the Old 

 World and in America, where the extreme southern forms 

 are known as U. armcniacus and E. coluviM or tcxanus 

 respectively. Xo mammoths, however, were larger than the 

 modern Indian elephant, and they can only be said to have 

 commonly exceeded this living species in the development 

 of their stout curly tusks, of which several fine examples 

 (one from Eschscholtz Bay measuring 12 ft. 6 in. along the 

 Pier-case curve) are shown in Pier-case 29 (30) and on the top of this 

 29 (30). j^j^j adjacent Pier-cases. These tusks are so common and so 

 well preserved in some parts of the Arctic regions, that they 

 are a valuable source of ivory and have long been collected 

 as an article of commerce. The mammoth is, indeed, best 

 known from discoveries within the Arctic circle, where not 

 only the fresh bones and teeth but also whole carcases are 

 occasionally met with in the frozen earth. One such carcase 

 was made known to science a century ago by Adams, who 

 found it at the mouth of the Lena and brought the greater 

 part of the skeleton, with the head and feet still covered by 

 the skin and soft parts, to St. Petersburg in 1806. Photo- 

 graphs of this skeleton, as it is now mounted with some 



