﻿lxviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxii, 



Dr. R. Broom, Dr. E. C. Case, and others, and a critical summary 

 of the results was published by Dr. Case last summer. 1 It now 

 appears that all the specializations in the American groups were in 

 the direction of higher reptiles ; while all those in the South 

 African groups made a progressively closer approach to mammals, 

 and as nearly as possible culminated in typically mammalian 

 skeletons. Hence, although we have evidence of two possible 

 sources of mammals, only one appears to have produced them. 



Secondly, consider a case of less fundamental character, the 

 origin of the Monkeys or lower Anthropoidea. It is generally 

 admitted that they arose from the next lower grade, that of the 

 Lemurs or Lemuroidea, which were almost universal in their 

 distribution over the great continents at the beginning of the 

 Tertiary Era. It is also suspected (though the palseontological 

 evidence is still very scanty) that the two markedly distinct groups 

 of Monkeys, the Platyrhines in America and the Catarhines in the 

 Old World, were derived independently from the Lemurs in these 

 two separate continental areas. If this be so, a zoologist's ' sub- 

 order ' has arisen by two parallel, though readily distinguishable, 

 developments from an earlier and lower 'sub-order.' Now, the 

 surviving Lemurs of the Asiatic and African regions and Mada- 

 gascar have lived on from early Tertiary times practically un- 

 changed ; but there is one isolated area, the island of Madagascar, 

 where some families during the later Tertiary periods attained 

 remarkable specialization. Unfortunately, we only know the 

 Pleistocene and Holocene members of these families that are 

 discovered in the caverns and swamps of Madagascar ; but they 

 represent the culminating genera, and suffice to indicate what 

 happened. In this isolated region the highly-specialized late 

 Tertiary Lemurs curiously resembled in some characters both the 

 Platyrhine and the Catarhine Monkeys. The first portion of skull 

 of Nesopithecits, in fact, appeared to so experienced an observer as 

 Dr. Forsyth Major so monkey-like that he originally placed it 

 among the Monkeys, in a new family intermediate between the 

 South American Cebidse and the Old- World Cercopithecidse. It 

 is now clear, however, from the researches of Dr. G. Grandidier 

 and Dr. H. F. Standing, that none of these animals really passed 

 beyond the typical Lemur-grade. They eventually grew large, 



1 E. C. Case, ' The Permo-Carboniferous Eed Beds of North America & 

 their Vertebrate Fauna' Publication 207 (1915) of the Carnegie Institution 

 of Washington, p. 121. 



