446 PRINCIPAL SIR WM. TURNER ON 



In two Scottish skulls in the University Museum the tracings showed the breadth at the 

 post-orbital depression to be a little more than the supra-orbital breadth, the index in 

 each specimen was more thai) 100, and the mean was 102*1. In the outline drawing, 

 fig. 5, the difference in the post-orbital depression in the Tasmanian and the Scottish 

 skull can at once be recognised. The small number of specimens measured in each race 

 scarcely sufficed as a basis for a wide generalisation, but as far as they go the Australian 

 index was less than that in Pithecanthropus, in the palaeolithic Spy skulls and the 

 Tasmanians. As of these skulls the Tasmanians had the highest index, they approached 

 nearer to the post-orbital index in the Scottish skulls, and in No. 5 the index was 91 '4. 



The glabello-inial diameter in each skull was not quite equal to the maximum 

 length of the skull, which is to some extent regulated by the degree of projection of 

 the occipital squama, associated with the growth of the occipital end of the brain. 



In my descriptions of the Tasmanian skulls I have referred to their marked phceno- 

 zygous character, a condition which is produced not only by the arching of the 

 zygoma, but by the depth of the post-orbital depression, and the tendency to flattening 

 of the squamous temporal. The deep concavity of the outer surface of the ali-sphenoid 

 materially contributed to the post-orbital depression, and the infra-temporal crest, 

 which separated the temporal and zygomatic parts of this surface from each, other, 

 was scarcely to be seen in some of the crania.* The horizontal outline of the 

 Tasmanian skull corresponded, in the post-orbital depression, with those figured by 

 Klaatsch from skulls in the museums in London and Paris. In the Australians the 

 skulls were also phcenozygous, but the surface of the ali-sphenoid was not so deeply 

 concave as in the Tasmanians. In the Scottish skulls the zygomata were not visible in 

 the norma verticalis, i.e. cryptozygous, the ali-sphenoid was only slightly concave, 

 and the transverse diameter at the temporal lines was wider than in Australians and 

 Tasmanians. 



In one of my Tasmanian skulls, No. 10, the ali-sphenoid was cut off from the parietal 

 by a tongue-like process of the squamous which articulated with the frontal, and in 

 three an epipteric bone, or bones, was present on one or both sides. The parieto- 

 sphenoid articulation varied from 5 to 1 1 mm. in the series of skulls. In the Challenger 

 Report, 1884, I reviewed the variations in the pterion in the skulls of man and apes, 

 and referred to Australian, Papuan, Melanesian, Polynesian, European and other skulls 

 in which I had seen the squamoso-frontal articulation and epipteric bones, though the 

 frontal process of the squamous temporal occurred more frequently in the lower races 

 than in Europeans. In a previous paper in which I had described skulls of the gorilla t 

 I had pointed out that, whilst the squamoso-frontal articulation seemed to be the rule in 

 the gorilla and chimpanzee, in the orang again the ali-sphenoid sometimes articulated 

 directly with the parietal, at others it was separated from it by a squamoso-frontal 



* Klaatsch noticed the barely marked infra-temporal crest in the Tasmanian skull in the Sydney Museum. 

 t 1'roc. Roy. Hoc. Edin., vol v. p. 344, 16th Jan. 1865. Three skulls, adult male and female and a young one, 

 which had been collected by M. du Chaillu, and had been presented to the Anatomical Museum. 



