166 EVOLUTION IN THE PAST 



gratulations, though not feasible, were well deserved, for the 

 animals were insusceptible of any essential modification of 

 their land-designed machinery for breathing, and for the 

 bringing forth and suckling of young. 



SEALS Other mammals, it is clear, had followed the example of 

 the whale-ancestors by relinquishing land for a sea life. The 

 exchange of elements in this case had resulted in seals, a 

 few species of which were now in view (Prophoca). Their 

 tangled course of descent is quite unknown. Their nearest 

 relatives in the Miocene were probably the otters. 

 BIRDS More remarkable than the evolution of seals and whales 

 from land-mammals was the rise of birds from reptiles, and 

 their subsequent development into a vast variety of forms. 



Deficient though be the record, several glimpses of the 

 progress have been yielded by Miocene strata. 



In river-swamps and fenny solitudes heron quite of modern 

 type were seeking their miscellaneous food (Ardea). Storks 

 were much more in line with present-day forms. Some, 

 indeed, seem to have been of the same genus as the Adjutant 

 Stork (Leptotilus) ; others were primitive wood-ibises (Tan- 

 talus}. New forms of more or less plover origin had become 

 specialised as auks, guillemots, and curlew (Mancalla, Uria, 

 Numenius). Gulls, an earlier offshoot of the stock, probably 

 consisted at this time of many species. 



Turkeys, hardly semi-existent, so far as is known, in the 

 Eocene, had now become completely evolved in North America 

 (Mdeagris). And plantain-eaters (relatives of parrots) aug- 

 mented bird-life in Europe, where a genial clime provided 

 them with bananas and other fruits they loved (Necrornis). 

 CROCODILES The continuance of a widespread warmth enabled crocodiles 

 and alligators to thrive in scenes which are now denied 

 them ; and crocodiles, indistinguishable from long-snouted 

 forms now confined to the tropics, were haunting European 

 rivers (Tomistoma). 



CHELONIANS Huge tortoises, allied to the Greek Tortoise, were creep- 

 ing about the inland scenes. Water-haunting forms, known 

 as alligator terrapins, were in the lakes and tidal waters 

 (Chelydra) ; and turtles closely allied to the Hawksbills or 

 tortoise-shell-bearers were also in evidence (Chelone girondica^ 



