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CHAPTER III 



the cases here treated. We have to reahze that they indicate an old contact, only in 

 some few insects expressed through identity of species, nota bene, of a primitive 

 and no doubt old type, otherwise in genera and families in common, and that we 

 must go well back in Tertiary' time for an explanation. Great faunal changes indeed 

 have taken place since then. 



This may be illustrated by an example. The Cryptobranchidae among the Sala- 

 manders are represented in the recent fauna of the earth only by the well-known 

 "Giant Salamander", Megalobatrachus maximus Schleg., of China and Japan, and 

 Cryptobranchus alleghaniensis Daud. from the Mississippi basin. But the European 

 fossils from Miocene referred to genus Andrias (the famous A. scheuchzeri Tschudi, 

 "Homo diluvii testis", and others), according to Herre (1935, p. 48), are generically, 

 possibly even specifically, identical with the still living Megalobatrachus. Supposing 

 the contrary had happened, that the European form had happened to survive but 

 the East Asian had become extinct and no fossil remains discovered,— and we 

 would have had a perfectly Eur-American family of Salamanders, with several 

 false theories as a consequence. 



The Baltic amber of Europe, usually considered of late Eocene age, contains 

 numerous examples of genera, families or higher taxonomic categories, parti- 

 cularly of insects, now absent from the continent or even from the entire Holarctic 

 region, examples of which are given below. As argued by Darlington (1948, p. 

 2 a.f.), recession and extinction plays a role equal to evolution and spreading in 

 faunal history, and extinction usually starts with the division of one large area into 

 small, separate ones. 



The Amphiatlantic animals of the more southern type here treated apparently 

 all have entered this stage of recession. They are remnants of a large, though not 

 necessarily contemporaneous, area across the Asian continent. Thus I can add very 

 little to the views expressed by Matthew (191 5), Reinig (1937), Schmidt (1946), 

 Simpson (1947), Darlington (1948), and others. 



The present distribution of these animals is of pronounced relict character and 

 necessitates no other change in extension of the present continents than the unani- 

 mously accepted Bering land bridge. 



Wegener — pro and contra 



The hypothesis of continental drift was in part based on biogeographical data by 

 Wegener himself (1929, p. 99-124) and subsequent students accepting his idea 

 have often used examples of animal distribution as confirmation. 



Several zoologists and some botanists at first more or less enthusiastically accepted 



