296 PROFESSOK D. J. CUNNTNGHAM ON 



there is the figure of the skull of a young female gorilla in which the superciliary 

 element of the torus supraorbitalis is distinctly seen (12, fig. 112, p. 102). It is still 

 more evident in the skull of an adult male chimpanzee in the Anatomical Museum of 

 the University of Edinburgh. The photograph of this skull is given in PI. I., fig. 15. 

 Transition forms between Type II. and Type III. of the supraorbital region are thus 

 met with in both the chimpanzee and the gorilla. 



Of the nineteen skulls of the adult chimpanzee which I had the opportunity of 

 studying in the British Museum, three presented this transition form. In one (Museum 

 No. 2, c. 1130) the condition was particularly strongly marked. The torus supra- 

 orbitalis was divided into two distinct parts, the inner two-thirds, which contained the 

 superciliary element, being very prominent as compared with the outer third.* This 

 is to be looked upon as being merely the retention of a juvenile character. It is the 

 rule in the young chimpanzee for the brow-ridges to begin to assume form at the time 

 when the milk-teeth erupt. In the early stages it is generally possible to distinguish 

 the superciliary element in the torus supraorbitalis ; but, as a rule, after the second molar 

 tooth has made its appearance the superciliary eminence becomes completely blended 

 with the other elements which build up the torus, and the supraorbital projection assumes 

 its typical form. 



In the adult gorilla, the amalgamation of the different elements in the torus supra- 

 orbitalis is so complete that little indication of the composite character of the latter can 

 be detected. Still, when the arch is viewed from above a general fulness in the super- 

 ciliary region points to the presence of the superciliary element. I have not had the 

 opportunity of studying the condition in the skull of the young gorilla. 



The supraorbital region in the Neanderthal, Spy, and Krapina remains presents 

 features which place it within Type III. As Schwalbe has shown, the different elements 

 have become blended in a strongly projecting torus supraorbitalis, in which there is little 

 or no indication of its composite character. This undoubtedly forms one of the leading 

 features of the race, but Schwalbe is in error in concluding that the possession of an 

 eyebrow region of this formation is the exclusive property of the Neanderthal group. 

 Individuals are met with in recent races in whom the same formation may be seen in 

 different degrees of development, and many specimens occur which present transition 

 forms between Type II. and Type III. 



In all large collections of Maori and New Guinea crania individual specimens which 

 belong to Type III may be found ; but in these cases the torus supraorbitalis, while show- 

 ing a complete fusion of the superciliary and supraorbital elements and the formation of 

 a continuous and uniform arch above the orbital opening, does not attain a great degree 

 of projection, nor does it take much share in the formation of the orbital roof. 



Amongst the Australian crania the case is different. Occasional specimens will be 



* In another specimen (Museum No. 2a) the appearance presented by the supraorbital region strongly resembles 

 the form usually seen in the aged baboon. A very evident groove (most evident on the left side) limits the super- 

 ciliary element on its outer side. 



