NO. 12 JAW OF PILTDOWN MAN MILLER 5 



reproduced by similar mutilation of the articular process of No. 

 174699, an adult female chimpanzee from French Congo. The argu- 

 ments from anatomy, like those from geology and geography, are 

 thus seen to have little force. 



Mandibular Characters of the Anthropoidea 



Before trying to decide how much importance should be assigned 

 to the peculiarities of the Piltdown jaw it is necessary to understand 

 the more conspicuous mandibular characters of the Anthropoidea. 



In the Hominidce 1 as in all other Anthropoidea the mandibular 

 halves become completely ossified at the symphysis soon after birth. 

 This character distinguishes members of the order from the recent 

 Lemuroidea, in all of which the halves remain distinct. Two main 

 peculiarities of the lower jaw and its toothrow separate the Hominidce 

 from other Anthropoidea and especially from the great apes. The 

 two halves of the jaw together form a horseshoe-like arch (text 

 fig., 1 and 3, and pi. 3), so broadly rounded in front that the width 

 between the anterior molars is decidedly greater than the distance 

 from the first molar to the symphysion, and so widely open behind 

 that the distance between the condyles (outer borders) is conspicu- 

 ously greater than that from condylion to symphysion. In other 

 members of the order the arch is so narrow that the distance between 

 the anterior molars never exceeds that from first molar to the sym- 

 physion, and the distance between the condyles rarely if ever equals 

 that from condylion to symphysion (text fig., 2, and pi. 4). The 

 toothrow in the Hominidce is narrowed and weakened in front of the 

 molars, the change taking place abruptly with posterior premolar. 

 Each premolar is single rooted, and the crown-area is less than half 

 that of the first molar. The canine never projects conspicuously 

 above the general level of the other tooth summits ; its size, form and 

 function are essentially incisor-like. Among the great apes the 

 robust character of the toothrow is carried forward through the 

 large, double-rooted premolars to the strongly functional canine, the 

 point of which rises in males conspicuously above the general level 

 of the other teeth. Together with its anterior weakening the tooth- 

 row as a whole is characterized in the Hominidce by a widely arched 

 form corresponding to that of the jaw. The inward curve on each 



1 Including the various living species of Homo and the pleistocene H. 

 neanderthalensis King and H. heidelbergensis Schoetensack, but excluding, as 

 members of the family Pongidce, the genera Pithecanthropus Dubois and 

 Sivapithecus Pilgrim. 



