vi] DISTRIBUTION OF SELECTED GROUPS 11 





hitherto not one single marsupial fossil is known 

 from India, nor from any other part of Asia. 



Many pre-Tertiary mammalian remains are known 

 from Europe, North and South America, mostly 

 nothing but teeth and under-jaws. Presumably all 

 the Jurassic and Lower Cretaceous mammals were 

 Metatheria, leaving aside the Monotremes, q.v., but 

 it is often impossible to decide whether the Upper 

 Cretaceous and even some of the Eocene creatures 

 were still in the Metatherian stage, whether they were 

 already Placentals or whether they were typical mar- 

 supials. We begin to discern three great groups. 



1. Archaic Metatheria with Diprotodont ten- 

 dency. The so-called Multituberculata or Allotheria, 

 e.g. Microlestes from Upper Trias of Europe ; Plagi- 

 aulax from Upper Jurassic of Europe and North 

 America ; Meniscoessus from Upper Cretaceous of 

 North America; Polymastodon and Neoplagiaidax 

 from North America and European Palaeocene. 

 Others, supposed to be related to the Allothema, 

 have been described from Patagonian Cretaceous 

 and Eocene deposits. But these Allotheria (i.e. 

 1 different beasts ') have not much to do with the true 

 marsupials, certainly not with the Diprotodonta, 

 although they are diprotodont, a feature which has 

 been evolved at various times and by various orders. 

 However, the Allotheria, of which many remnants 

 are known, mostly from Wyoming and Patagonia, 



