472 



DISTRIBUTION IN SPACE AND TIME 



LIFE IN THE KAINOZOIC EPOCH 



Even in the earlier stages of the Kainozoic epoch we find 

 that the fauna had a comparatively modern aspect, and the later 

 stages ultimately merge into the present. Among backboned 

 land -animals Mammals and Birds were dominant, and it will 

 be as well to confine our attention to a few interesting facts con- 

 cerning these groups. 



KAINOZOIC MAMMALS (MAMMALIA). The fossil remains which 

 have so far been examined enable us to trace the gradual evolu- 

 tion of the subdivisions of several mammalian orders, notably 



Fig. 1331. Restoration of Phenacodus (reduced) 



so as regards Hoofed Mammals (Ungulata) and Flesh-Eaters 

 (Carnivora). In the earliest stage of the epoch we find the 

 ancestors of the hoofed forms represented by small primitive 

 swamp-dwellers, constituting an extinct group (Condylarthra), of 

 which a well-known type (Phenacodus] is represented in figs. 1331 

 and 1332. By increasing complications of structure, affecting 

 limbs, teeth, brain, &c., the various odd-toed and even-toed un- 

 gulates have sprung from creatures of the kind, as also Conies 

 (Hyracoidea), and, most probably, Elephants (Proboscidea]. The 

 nature of some of the specializations which took place have been 

 briefly explained in a previous section (see vol. iii, p. 137). 



What is true for Hoofed Mammals as regards one primitive 

 group is also true for Flesh- Eaters with reference to another 

 such group (Creodonta). Indeed there is not a great deal 



