648 MANUAL OF ZOOLOGY. 



sabre-shaped upper canines. Species of this genus must have 

 been as large as a Lion. In the later Pliocene and Post- 

 pliocene deposits occur the remains of a large Lion the 

 Cave-lion or Felis spelcea along with which, in Britain and 

 continental Europe, are the bones of a large Hyaena (H. 

 spelcea) and a gigantic Bear (Ursus spelceus}. Remains of 

 Wolves, Foxes, Badgers, Otters, Pole-cats, Weasels, and other 

 Carnivora are also found in various later Tertiary deposits, 

 and in bone-caves. 



Order X. Rodentia. No Rodent animal is as yet known to 

 have occurred earlier than the Eocene period. Here are found 

 froms allied to the living Dormouse and Squirrel. In the 



Miocene rocks occur nume- 

 rous small Rodents. In the 

 Pliocene and Post-pliocene 

 deposits the order is also well 

 represented, the most remark- 

 able form being the Great Bea- 

 ver (Trogontherium, fig. 280), 



Fig. 2 8o.-J^of Trozontherium Cuvieri. which appears tO have Survived 



Post-pliocene. into the historical period. 



Order XL Cheiroptera. The earliest-known indications of 

 Bats are in the Eocene period, but the order is of no geological 

 importance. 



Order XII. Insectivora. The Insectivorous Mammals, like- 

 wise, commenced their existence, so far as is known, in the 

 Eocene period; and they, also, are of little importance from a 

 geological point of view. 



Order XIII. Quadrumana. With two not wholly satisfactory 

 exceptions, from the Eocene Tertiary, the earliest-known 

 remains of Quadrumana occur in the Miocene period. Several 

 genera are known, but the most important are Pliopithecus and . 

 Dryopithecus, both of which are European, and both of which 

 belong to the section of the Catarhine Monkeys, which are at 

 present characteristic of the Old World ; the former being most 

 nearly allied to the living Semnopitheci, the latter to the Gib- 

 bons. It is interesting to notice that the American fossil 

 Monkeys from the later Tertiary deposits of South America 

 belong to the division of the Quadrumana now peculiar to that 

 continent to the section, namely, of the Platyrhine Monkeys. 



GEOGRAPHICAL SUCCESSION OF ORGANIC FORMS. 



A few words may be said here on a law which may be called 

 the " law of the geographical succession of organic forms/' and 



