212 PROCEEDINGS OF THE ACADEMY OF [1862. 



would not have given rise to the discussion between Pansch and 

 Bischoff already referred to. On the other hand the Gorilla agrees 

 with the Orang in the superficial disposition of the occipital con- 

 volutions, the operculum, so conspicuous a feature in the brain of 

 the Chimpanzee, being absent. If it be permitted in the absence of 

 living links or sufficient fossil remains to speculate upon the devel- 

 oj^ment of Man and the anthropoids from lower forms of simian life it 

 might be inferred from the character of the brain that the Gorilla 

 had descended from some extinct Cynocephalus ; the Chimpanzee 

 and Orang from extinct Macacque and Gibbon-like forms, and 

 Man from some generalized simian form combining in itself the 

 characteristics of existing anthropoids. The remote ancestors of 

 such extinct forms, to recede still farther in geologic time, such 

 as Necrolemur of Filhol, Notliarctus of Leidy, Lhnnotherinm of 

 Marsh, Anaptomorphus of Cope, the latter the most simian 

 Lemur yet discovered, resembled, as their names imply, the living 

 Lemurs of the present day, intermediate forms connecting the extinct 

 and existing genera having once lived but having now passed away. 

 Notwithstanding the value and importance of the remains of Meso- 

 donts, Prosimiseand Lemurs discovered, especially by Leidy, Marsh 

 and Cope, in the eocene formations of the Rocky Mountains, a much 

 more complete series of simian remains than is now available must 

 be placed at the disposal of the evolutionist before even a general out- 

 line of the geneology of Man and the remaining primates can be 

 established. 



