PRIMITIVE MAN- IN CHINA SMITH 543 



months of intensive work, Dr. Davidson Black completely liberated 

 the skull from the matrix of travertine, the braincase was revealed 

 with a curious blend of characters hitherto regarded as distinctive, 

 some of them of Pithecanthro'pus and others of Eoanthroyus. The 

 combination in the same specimen of peculiar characters hitherto 

 regarded as incompatible one with the other was not only important 

 as a revelation of the extremely primitive and generalized qualities 

 of Sinanthropus^ but, what was even more important, it formed a 

 link between the other two genera of early Pleistocene men, concern- 

 ing the validity and significance of which there had been so much 

 doubt and suspicion. Hence the skull found in 1929 not onlj'- estab- 

 lished on a firm foundation our knowledge of primitive man to which 

 it gave coherence and in which it inspired confidence, but in addition 

 it revealed a type which was so primitive as to enable us to visualize 

 the characters of the common ancestor of all three genera. 



If the size and form of the eyebrow-ridges (pi. 4) and the median 

 frontal crest (pi. 2) suggest a kinship with Pithecanthropus^ the 

 form of the posterior aspect of the skull (pi. 1, fig. 2) presents a 

 marked contrast to the Java fossil and a definite likeness to 

 Eoanthropus. 



As long ago as 1903, Professor Schlosser defined the contrast be- 

 tween the tooth he was discussing and those of Pithecanthropus, 

 differences which have been still further emphasized by Dr. Davidson 

 Black with the fuller material at his disposal. 



The braincase of Sinanthropus differs from that of Pithecan- 

 thropus not only in the matter of the local expansions of the frontal 

 and parietal areas, but also in its general form and the characters 

 of its cranial bones, for the exceptional thickness of the cranium 

 (pis. 5 and 6), and the peculiar architecture of the bones repro- 

 duce conditions which hitherto have been regarded as distinctive 

 of Eoanthropus. The form of the surprisingly small cranial cavity 

 presents a significant contrast to that of Pithecanthropus, being nar- 

 rower and loftier, and free from the grosser type of distortion re- 

 vealed in the broad flat endocranial cast of Pithecanthropus. The 

 braincase of Sinanthropus reveals many features which are un- 

 known either in the Ape Man of Java or in the Piltdown skull, and 

 throws a great deal of light upon the characters of the common 

 ancestor of the human family, from which all these genera had been 

 derived. One of the most striking illustrations of this fact is the 

 peculiar form of the mastoid region of the temporal bone, recalling 

 as it does the condition found in the new-born child and in the adult 

 anthropoid apes, for it lacks that salient character which is so 

 distinctive of the adult human of other genera (pis. 3 and 4, fig. 1). 



