228 PAN 



are permanent from yowth to the adult state, what, if any, are the 

 distinctions in color between the sexes, (in some species we know there 

 is no difference, but in others we are not so sure) ; what are the limits 

 of the dispersion of those we gaily describe as distinct — do two or 

 more species or races, call them what you will, dwell together in amity 

 retaining their distinctive characteristics within limited areas ; all these 

 problems and more arise to greet us, and for the most of them we have 

 no answer. 



The material gathered in most Museums is so small and unsatis- 

 factory, that it is of no avail in deciding the facts we all seek. The 

 best, and so far as I have found, the only considerable collection of 

 these animals extant to-day, is in the Berlin Museum, where about 

 eighty skins and perhaps as many skulls have been brought together 

 from different parts of Africa. But when we study these, we con- 

 stantly meet with difficulties that not only perplex us, but prevent any 

 satisfactory decision from being reached. It is easy enough to solve 

 a difficulty by describing some troublesome specimens as new, and 

 leaving the proof for some one else to discover, but that does not solve 

 legitimate doubts, nor help overmuch to teach us the truth we desire 

 to know. 



In seeking for characters upon which specific differences may be 

 founded we naturally first examine the crania, and at once we are 

 confronted with a fact that prevails among all the great Apes, that 

 individual variations exist to such an extent, that no one character can 

 be depended upon, for no two skulls are alike, and they differ from each 

 other in a manner equally great as is observed among human skulls. I 

 have already commented upon this fact when discussing the specific 

 values of specimens of the Gorilla and Ourang-utan, where in the 

 latter I was compelled to decline to recognize more than one species 

 after most careful investigation of a very large series of crania ; and 

 to recognize only with great doubt certain forms of Gorilla as possible 

 species, not on any cranial character, but simply on the color of the fur 

 which eventually may prove, as our knowledge of these animals 

 increases, to be merely phases of pelage attributable solely to age. Cer- 

 tainly neither among Gorillas nor Ourang-utans can any specific differ- 

 ence be safely based upon cranial characters, and in this respect the 

 Chimpanzees are no exception. At present, therefore, we rely mainly 

 for our specific characters of these animals upon the texture, length 

 and color of the hair ; the presence or absence of beard ; color of the 

 face; sometimes of the hands and feet; seldom on the teeth, (for 

 characters among these are rarely found), the extent in which the face 



