CENOZOIC TIME — QUATERNARY. 1017 



were common species. Australia is now and has been through the Quater- 

 nary the continent of Marsupials and Monotremes ; and the same types were 

 almost its only Mammalian population in the Tertiary. North America, dis- 

 tinguished for its large number of Pleistocene Herbivores and relatively few 

 Carnivores, was equally so distinguished during the Tertiary ; while Eurasia, 

 in both the Tertiary and Quaternary eras, was the chief region of Carnivores. 

 The principle could be illustrated by examples from tribes and species 

 throughout the kingdoms of life; but this would be out of place here. It is 

 explained by Darwin on the ground that the Quaternary kinds have been 

 derived from the Tertiary by descent ; and this explanation is now generally 

 accepted. The exceptions to the rule have come chiefly through migration. 



Progress in degeneration. — The most prominent cases of degeneracy in 

 terrestrial Quaternary Maiaimals occur in the Edentates. A great popula- 

 tion of them lived in South America, pertaining to numerous genera against 

 two in Europe, Asia, and Africa. The Glyptodonts (Figs. 1563, 1564) 

 appear to have been the lowest. The thick bony covering is protective, and 

 very completely so. It is Molluscan in idea. From what higher Mammals 

 they descended is not known. The low-grade characteristics seem to be a 

 consequence of inactive habits or sluggishness as a- result of freedom from 

 enemies and from all unsatisfied desires. Degeneracy from inactivity is well 

 exemplified in parasitic Crustaceans, as the Lernaeans, which live with the 

 head-end inside of a fish, always content. As a consequence they have 

 become worm-like in body, and almost limbless and senseless. There is 

 here, emphatically, degeneracy through disuse, with adaptations to the con- 

 ditions ; their origin is thus explained by disuse and adaptation without 

 reference to the "survival of the fittest," or "natural selection." The 

 same is true of the Megatheria ; their legs became reduced nearly to massive 

 pedestals by inactivity, and the front teeth, as in other Edentates, were lost 

 through disuse. The Glyptodonts degenerated on the same principle ; but, 

 through some organic tendency (like that less perfectly illustrated in the 

 Turtles, the most sluggish of Reptiles), ossification gave them — and emi- 

 nently so Doedicurus — a protective covering almost to their destruction. 

 It was fitted to save from Carnivores, but not from the cooler climate that 

 ensued, and so the later fauna of the region was rid of them, — exemplifying 

 the fact that the principle of the " survival of the fittest " determines the 

 species that survive to constitute new faunas, if not the existence of new 

 species. The first of the Glyptodonts appeared in the Miocene. 



Man. — Man stands in the successional line of the Quadrumana, at the 

 head of the Animal Kingdom. But he is not a Primate among Primates. 

 The Quadrumana are, as Cuvier called them, Quadrumana from the first to 

 the last. They are Brute Mammals, as is manifested in their Carnivore-like 

 canines and their powerful jaws ; in their powerful muscular development ; 

 in their walking on all fours, and the adaptation thereto exhibited in the 

 vertebrae, producing the convexity of the back ; and also in other parts of the 

 skeleton. 



