284 SCIENCE PROGRESS 



when judged by equine or elephantine standards. I will revert 

 to this matter shortly, in describing the diagram, but it is clear 

 at once that the rate of evolution in one order is no criterion 

 whatever of the rate of evolution in another. 



Fossil remains of apes — I use the word " ape " in its strict 

 confined sense, referring only to the Simiidae — have been dug 

 up from time to time during the last sixty years, but unfor- 

 tunately the remains are of a very fragmentary character. It 

 is necessary to insist upon this point. Simian relics have been 

 found in various strata from the Oligocene to the Pleistocene, 

 but the relics consist in most cases merely of lower jaws, and, 

 indeed, two genera have been founded on the strength of a few 

 teeth. It is important, therefore, to speak of the Oligocene and 

 Miocene apes with all due caution. For aught we know to the 

 contrary, these ancient creatures may have been nearer to their 

 ancestors the Old- World monkeys (Cercopithecidae), in various 

 points of their anatomy, than are the Simiidae living now. 

 When all allowance is made, however, for this element of 

 uncertainty, there remains at least a high degree of probability 

 that the ape-like relics do really represent animals which were 

 more ape-like than monkey-like. 1 



The simian fossils may be briefly enumerated, without 

 entering into great anatomical detail, which is unnecessary for 

 the purpose in hand. Indeed, the phylogenetic significance of 

 the morphological details has not thus far been worked out with 

 any thoroughness, although a most interesting contribution to 

 the subject was recently made by Dr. Smith Woodward. 1 The 

 reader may be reminded that the lower apes, collectively known 

 as gibbons, probably stand nearer to the common ancestor of 

 the Simiidae and the Hominidae than do the higher apes — the 

 chimpanzee and its kin, which seem to represent a more 

 divergent twig of the phylogenetic tree. The notoriously 

 gibbonoid characters of the lowest of the known Hominidae, 

 the Javan ape-man, are thus explicable. Perhaps we should 

 call the common ancestor a gibbon if we could meet him in 

 the flesh. We should therefore expect the gibbons to be more 

 ancient than the higher apes, and this is now proved to be 

 the case. 



Nothing is known of the history of the gorilla, or of that 



1 See paper read to the Geological Society on April 29, 1914. 



