THE CHIMPANZEES AND ORANGS. 177 



The Pithecus Morio may, therefore, quoad its origin, be an old-estabUshed, and now 

 permanent, dwarfed variety of the Pith. Satyrus. I apprehend that few naturahsts, 

 now-a-days, in describing and proposing a name for what they call " a new species," use 

 that term to signify what was meant by it twenty or thirty years ago, that is, an 

 originally distinct creation, maintaining its primitive distinction by obstructive gene- 

 rative peculiarities. The proposer of the new species now intends to state no more 

 than he actually knows ; as for example, that the differences on which he founds the 

 specific character are constant, in individuals of both sexes, so far as observation has 

 reached ; and that they are not due to domestication or to artificially superinduced exter- 

 nal circumstances, or to any outward influence within his cognizance ; that the species 

 is wild, or is such as it appears by nature. It becomes, therefore, a matter of con- 

 venience, if not of necessity, to indicate the species by a distinct name, in the imparting 

 of zoological knowledge. 



The justification of such a procedure depends on the kind and degree of evidence, 

 and I believe that I have at length been enabled to record such evidence, in regard to 

 the Pithecus Morio, in the 'Transactions of the Zoological Society.' 



DESCRIPTION OF THE PLATES. 



PLATE XLVIII. 



Side view of the skull of an adult male Pithecus Morio : nat. size. 



PLATE XLIX. 



Fig. 1 . Base view of the same skull : nat. size. 



Fig. 2. Grinding surface of the lower teeth, right side : nat. size. 



PLATE L. 



Fig. 1. Top view of the skull of an adult male Pithecus Satyrus, var. Pappun : half 



nat. size. 

 Fig. 2. Grinding surface of upper molars and canine, left side : nat. size. 

 Fig. 3. Top view of the skull of an aged male Pithecus Satyrus (the variety called 



Mias Rambi by Blyth), with separated temporal ridges : half nat. size. 

 Fig. 4. Grinding surface of upper molars and canine, left side : nat. size. 

 Fig. 5. Grinding surface of lower molars and canine, right side : nat. size. 



