14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 65 



by the constantly increasing lambdoid crest. The fact that the 

 squamous portion of the occipital bone is well developed in the fossil 

 therefore indicates wide divergence from the known great apes. 

 Another fancied resemblance to the Pongidce is seen by Boule, who 

 remarks (191 5, p. 59) that to him the lower curved line appears to lie 

 relatively nearer to the upper curved line than in recent Homo, its 

 position thus more as in H. neanderthalensis and still more as in the 

 chimpanzees. The distance between the two lines in the Piltdown 

 skull is 15.5 mm. In two adult skulls of American Indians, one from 

 Illinois (No. 243881) the other from North Dakota (No. 228876), 

 which happened to be lying side by side in one of the exhibition cases 

 it is respectively 14.5 mm. and 2J mm. Among adult chimpan- 

 zees I find extremes of 15.5 mm. (No. 174700) and 24.5 mm. 

 (Nos. 84655 and 176227). When a character varies so much in both 

 genera no conclusion can be based on the conditions found in any one 

 skull. Even if a conclusion regarding the lines were justified it would 

 have little meaning in view of the strictly human features of all other 

 parts of the occipital bone. 



Aside from the superior maxilla the parts of the skull most directly 

 related to the mandible are: (a) the point of actual contact, (b) .the 

 region of origin of the masseter muscle, and (c) that of origin of the 

 temporal muscle. Of these three the first and last are well preserved 

 in the fossils. The glenoid region has been recognized as " typically 

 human in every detail" (Dawson and Woodward, 1913, p. 128). 

 Comparison with many human skulls shows that it presents the char- 

 acteristically human features of narrow articulating surface and deep 

 fossa in a much more than usual degree of development. Unfor- 

 tunately the absence of the condyle makes it impossible to know 

 whether the corresponding surface of the Piltdown jaw had the broad 

 and slightly convex form seen in all three genera of living Pongidce; 

 but the part immediately below the fracture shows, in the region 

 over the dental foramen, the highly developed strengthening ridge 

 characteristic of the genus Pan (see pi. 1) . A slight indication of the 

 ridge is often present in Homo; but I have been unable to find a 

 specimen even among those in a set particularly selected to illustrate 

 the variations of human mandibles, in which the structure of this 

 region agrees with living chimpanzees and the Piltdown jaw. The 

 facts are that the Piltdown skull presents extreme human character- 

 istics in the glenoid region calling for correspondingly extreme human 

 conditions of narrow and strongly convex articular surface in the 

 mandible which hinged on it. But this entire mandible, from sym- 



