364 SCIENCE PROGRESS. 



of smell is present. In the orang, for instance, the upper 

 turbinate bones are less developed (more rudimentary) than 

 in any of the higher primates, and the inter-orbital space is 

 proportionally narrower. Its extent also depends to some 

 degree upon the size of the ethmoid and lachrymal air- 

 sinuses. Notwithstanding, this space may be used, in the 

 primates at least, as some indication of the acuteness of 

 smell ; it may therefore be inferred, from the wide inter- 

 orbital spaces of the fossil men, that this sense was well 

 developed in them. 



10. WHAT ARE THE IMPRINTS OF SPEECH UPON THE 

 FACIAL PARTS OF THE SKULL, AND DO HUMAN 

 FOSSIL SKULLS POSSESS THEM? 



Of the facial parts of the human skull, specially modified 

 for speech, the prominent ascending nasal processes of the 

 superior maxillary, the short vertical alveolar borders of the 

 jaws, and the presence of a triangular mental eminence, are 

 amongst the chief. Unfortunately, only in Spy cranium 

 No. 1 are the superior maxillaries even fragmentarily 

 represented, but they have every indication of the usual 

 human conformation. 



Fortunately, however, the mental space or eminence is 

 completely preserved in two fossil jaws — the Naulette and 

 Spy No. 1. On these two jaws, as on those of all modern 

 men, the mental lines sweep forward above the inferior 

 borders of the jaw until they approach the symphisis menti, 

 when they turn up towards, and meet some distance below, 

 the incisor teeth. They cut off a rough, triangular space 

 with its base at the lower border of the bony chin, and its 

 apex directed towards the teeth. In most modern jaws 

 this space is raised so that it is in advance of the teeth, 

 presenting advantageous points of fixation for the inferior 

 labial muscles. In the fossil jaws the triangular space is 

 not raised; in the Naulette jaw it is flush with the inferior 

 incisors ; in the Spy jaw it is behind them. The arrange- 

 ment of the mental lines being the same in human fossil 

 jaws as in modern ones, one naturally infers that the 

 muscles which arose from them were adapted to similar 



