THE ABORIGINES OF TASMANIA. 439 



continuous with the supra-orbital border as a torus supra-orbitalis* (see Plate II. fig. 5). 

 These additional examples strengthen the statement by Klaatsch that the presence of 

 a torus supra-orbitalis in the Neanderthal type did not constitute a fundamental differ- 

 ence between it and modern man. In regard to the flattened condition of the frontal 

 bone between the supra-orbital border, external orbital process and the temporal ridge, 

 named by Schwalbe the trigonum supra-orbitale, I described the character many years 

 ago in the skulls of several Australian aborigines, and I stated that in this respect and 

 in the prominent glabella and superciliary ridges they approximated to the Neanderthal 

 cranium, t Since then I have pointed out this character in the Tasmanian skulls de- 

 scribed in Part I. of this memoir. 



The thickness and projection of the torus supra-orbitalis in anthropoid apes would 

 lead one to think that in them the height of the orbit would be diminished in correla- 

 tion with the thickness of the torus. On the contrary, in the anthropoids the orbital 

 aperture has a relatively high vertical diameter, a rounded outline, and therefore a high 

 megaseme orbital index. 



In order to give numerical expression to the character of the orbit in anthropoid 

 skulls, I have measured the width and height of the aperture in the specimens in the 

 University Museum and have computed the orbital index as in the human cranium. 

 The collection contains the skulls of seven gorillas, five adult males, one adult female and 

 a young specimen. In each adult the orbital width was somewhat greater than the height, 

 the index ranged from 76*5 to 95 '4 and the mean was 88"6. In the young gorilla the 

 height 40 mm. was greater than the width 35 mm., and the orbital index was 114*3. 

 In two adult chimpanzees the mean index was 94% and in two young skulls with the 

 milk dentition it was 9 6 '5. In four adult orangs the height was materially greater 

 than the width, the orbital index ranged from 108*1 to 122*5 and the mean was 114*4 ; 

 in two young skulls the mean was 106. In the skulls of five gibbons (Hylobates) the 

 index ranged from 87*5 to 104*1 and the mean was 93*9. 



In the Australians, again, a large proportion of the male skulls had prominent 

 glabella, superciliary and supraorbital ridges, and in all the specimens which I have 

 measured the width of the orbit invariably exceeded the height. In twenty males the 

 orbital index in eleven was below 80, five of which were below 75, and the mean index 

 81*4 was microseme ; the mean of nine women was 90, megaseme ; in four young skulls 

 the mean was 83*5, microseme. 



In the nine Tasmanian skulls which I have measured, the orbital index ranged 

 from 68*2 to 86*1, and the mean index was 79, i.e. microseme. 



In illustration of the two diameters of the orbit in Europeans, I may take the 

 dimensions obtained in my study of the Craniology of the people of Scotland. j 

 I measured 125 skulls, 84 men and 41 women. In two skulls the height exceeded 



* I did not give a figure of the eyebrow region of this skull in Part I., but fig. 5 in Plate II. of this Part shows 

 the character of the region. 



t Cliallenger Report, part xxix. p. 31, 1884. 



I 1'rans. Roy. Soc. Edin., vol. xl., part iii., p. 547, 1903. 



