294 



PROFESSOR D. J. CUNNINGHAM ON 



there is undoubtedly a tendency for the elements of the region to fuse together to form 

 a torus ; but in the fifty specimens I have examined I have not seen a skull in which 

 the coalescence is complete. There is always a trace of the groove which intervenes 

 between the superciliary eminence and the trigonum supraorbitale. Figs. 18 and 19, 

 PI. I., represent the usual appearance which is presented in this genus. In the middle 

 line the two superciliary arches are completely fused to form the glabellar eminence, 

 and here also they coalesce with the part of the orbital margin which lies to the inner 

 side of the supraorbital notch. From the glabella the two superciliary ridges arch 

 outwards like the two limbs of the letter Y, and, gradually tapering, each ends in the 

 neighbourhood of the temporal ridge. A strongly marked groove separates the super- 

 ciliary eminence from the trigonum supraorbitale. The term "trigonum" is hardly 

 appropriate for the part of the region which lies below and to the outer side of this 

 groove. It is true that it is a somewhat triangular area, but it is not flattened and 

 depressed as is usually the case in the human skull ; it is prominent, ridge-like, and 

 highly curved in accordance with the curvature of this part of the orbital opening. 

 This may be regarded as an approach to the condition termed by Schwalbe a " torus 

 supraorbital. " By the disappearance of the intervening groove and the consequent 

 coalescence of the superciliary eminence and the trigonum supraorbitale, the form 

 distinctive of the Neanderthal race, the gorilla, chimpanzee, etc., would be produced. 



The condition seen in the New Hebrides skull figured in PI. III., fig. 23, presents a 

 striking resemblance to the form of supraorbital region which we have described as 

 distinctive of the baboon. Two points of difference, however, are noticeable. The two 

 superciliary arches have drawn away from each other in the glabellar region, and their 

 inner ends are separated from each other by a shallow median groove. This is due to 

 the broadening of the forehead in man, and the coincident widening of the glabellar 

 region and of the interval which separates the orbits. In the baboon the narrow fore- 

 head is associated with a narrow glabella and a narrow root of the nose, and thus the 

 superciliary ridges are brought together in the middle line. The second point of 

 difference is in the trigonum supraorbitale. This area is flat and depressed in the New 

 Hebridean skull, although there is seen a tendency for the outer part of the supra- 

 orbital margin to form an arched prominence as in the baboon. 



Although not distinctive of any other group of apes, Type II. frequently occurs 

 in individuals of other genera and species. I have noted its presence in the follow- 

 ing specimens : — 



Semnopithecus (in two species, viz. aut 



Nasalis lanatus 



Cercopithecus . 



Cercocebus 



Mucacus (in eight different species) 



Presbytes maurus 



Calms (in four different species) 



In certain of the nine specimens entered in the above list as belonging to the genera 



ratus and cristatus) 



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