part 1] SECOXD skull feom the piltdowx geatel. 



Discussion. 



Mr. W. P. Pycraft exhibited a specimen of the right half of 

 a mandible of a chimpanzee, sent to him for examination by 

 Mr. (lerritt T. Miller, of the Smithsonian Institution, Washington. 

 Mr. Miller, in his Memoir on the Piltdown jaw, laid no little 

 stress on the importance of this specimen, from the fact that the 

 molars are worn so as to present flattened crowns similar to those of 

 the Piltdown jaw. Hence, this specimen formed a link in his chain 

 of evidence that the Piltdown jaw was unquestionably that of a 

 chimpanzee. 



It is clearty the jaw of an adult of one of the small races of 

 chimpanzee, and apparently of a female. But, as a witness for 

 Mr. Miller, it must be held to have failed ; because, although the 

 molars are worn flat, this is due, not to normal wear, but to some 

 interference in the normal * bite ' of the jaw caused by the 

 abnormal position of PM,, which projects above the lev^el of 

 the worn surface of the molars as much as 5 mm. That this is 

 not due to post-mortem displacement is clear, since the posterior 

 border of the crown, where it impinges upon the anterior border 

 of PM^, shows no sign of facetting as a consequence of the 

 mutual pressure of the two teeth. Nor does the crown show any 

 sis^n of wear. Unfortunately about half of this is missing, the 

 tooth having split longitudinally. 



The second premolar shows but very slight signs of wear, and is 

 conspicuously flat-topped — a feature peculiar to the tooth rather 

 than due to wear. 



The first molar is, as Mr. Miller described it, worn to a flat- 

 topped surface, but the wear has been from in front backwards, so 

 that the crown presents a decided backward slope when seen in 

 profile. 



The surface of M.^, though worn flat, is not in the same plane as 

 that of M^. This much can easily be demonstrated if a straight- 

 edge be placed over the two teeth ; a large wedge-shaped gap will 

 then be foimd between the straight-edge and Mp the apex of the 

 wedge being pointed forward. The worn surface of this tooth (Mj 

 is not absolutely flat, but presents a shallow depression running 

 from, the entoconid obliquely forwards to the protoconid. 



The incisors have been worn down to about half their original 

 length. 



In no other chimpanzee that the speaker had examined had he 

 ever found anj'thing in the matter of wear comparable with the 

 molars of Mr. Miller's specimen. These are quite abnormal in this 

 regard, and therefore of no value as evidence that the Piltdown 

 teeth might, even in the wear of their crowns, agree with teeth of 

 <3himpanzecs. Normally, one might affirm that the molars of these 

 animals never wear flat ; but the outer cusps disappear before the 

 inner cusps are perceptibly reduced b}^ wear. 



