NO. 12 JAW OF PILTDOWN MAN — MILLER 9 



it may bear extends obliquely between hypoconid and talonid. In 

 the third and most specialized type the paraconid is absent, the talonid 

 is not well developed except in m 3 , and the posterior half of the 

 crown is not basin-shaped. The region occupied by the hollow in the 

 other types is here filled by the bases of the hypoconid and entoconid. 

 Usually the bases of these cusps join to form a high, squarely- 

 transverse ridge. 



While the great apes and the Hominidce agree in the fundamental 

 structure of their lower molars each genus shows obvious characters 

 of its own. In Gorilla the crowns are low and the cusps high, sub- 

 terete and more conspicuous than in any of the others. The cingulum 

 on anterior border of m 1 sometimes bears a nodule which may be the 

 last remnant of the paraconid, a character which I have found in this 

 genus only. The talonid of m 3 is very distinct, often larger than the 

 hypoconid and often connected with the hypoconid by a rudimentary 

 oblique transverse ridge. The cingulum at the postero-internal border 

 of crown occasionally bears a minute cusp, while sometimes it is com- 

 pletely transformed into a well-developed single or double cusp. The 

 secondary folding of the enamel is evident, but not sufficiently devel- 

 oped to obscure the plan of cusp-arrangement. A low supplemental 

 cusp is sometimes present between the protoconid and the hypoconid. 

 In Pan the depressions between the cusps are not so deep as in 

 Gorilla, so that the crowns appear to be less brachydont and the cusps 

 less terete and less conspicuous. The talonid in m 3 is less developed 

 than in m 1 or m 2 , not larger than the hypoconid. Cingulum of postero- 

 internal border often so thickened as to form a supplemental cusp. 

 The secondary folding of the enamel is more evident than in Gorilla; 

 it tends to obscure some of the details of the cusp-arrangement. In 

 Pongo the cusps take the form of ridge-like elevations at the extreme 

 border of the shallow depression which occupies most of the surface 

 of the crown. The talonid is well developed but is somewhat obscured 

 by the flattening common to all the cusps and by the extremely con- 

 spicuous and complicated secondary enamel folding which covers 

 almost the entire surface of the teeth except the summits of the main 

 cusps. In the Hominidce the crowns are slightly less brachydont than 

 in any of the genera of great apes ; and the cusps are less distinctly 

 outlined by intervening depressions. Viewed from above they are seen 

 to be less squarely truncate, so that each tooth comes less broadly in 

 contact with the one in front of it (compare pis. 3 and 4) . This round- 

 ing off at the sides takes place in front at expense of both protoconid 

 and metaconid. There is a similar reduction at the posterior border, 



