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SCIENCE PROGRESS 



does Mr. Miller mean by a " few millimetres " ? Certainly not 

 less than 12, and probably 15 millimetres are missing. And 

 this amount amply suffices to show that the support for the 

 glenoid surface of the condyle, when restored by producing 

 the parieties of the mandible upwards, takes the contour char- 

 acteristic of the average human jaw much more readily than 

 of the average chimpanzee jaw, which, by the way, commonly 

 shows extremely prominent ridges and tubercles, for the 



Chimpanzee. 



Chimpanzee. 



Human, 

 i, 3. Torres Straits. 

 2. Uganda. 



Piltdown. 



Moriori. 

 Gond. 



Fig. 2. — Outlines showing the contours of the posterior border of the ascending ramus, and 

 of the condyle, in the jaws of chimpanzees and in human jaws. The condylar end of the 

 sigmoid notch is just indicated in each case. It is clear that the Piltdown jaw more 

 nearly conforms to the human than to the chimpanzee type. 



insertion of the internal pterygoid muscle (fig. 2), though 

 jaws in which these ridges are but slightly developed are also 

 found. They are never so prominent in the human jaw, and 

 they are barely perceptible in the Piltdown jaw. 



In regard to the comparisons drawn between the jaws of 

 chimpanzees and recent human jaws, and set forth in a Table 

 of Measurements on p. 20 of Mr. Miller's memoir, there 

 are several points which call for comment. Thus, in com- 



