PITHECANTHROPUS ERECTUS, ETC. 363 



of the cynocephalic type, sometimes in idiots, 1 but has never 

 been observed in anthropoid skulls. Its meaning is quite 

 unknown. 



Idiots' skulls" not unfrequently manifest these cynoceph- 

 alic characters, and it has been supposed that the Bengawan 

 skull may have belonged to such an individual. Although 

 idiot skulls manifest a great variety of forms, there has 

 never been one recorded that even approximates the con- 

 formation of the Bengawan skull. There is no reason why 

 an idiot may not have such a brain case as that of the 

 Bengawan ; only it must be excessively rare, and the 

 chances are enormously against such being found in a 

 fossil state. 



9. THE FACIAL PARTS OF FOSSIL SKULLS. 



The facial parts of the Bengawan skull are quite want- 

 ing. The supra-orbital ridge, which formed the upper 

 boundary of its face, measures from end to end 1 10 m.m., 

 and the corresponding ridges in the Neanderthal and Spy 

 crania slightly exceed 120 m.m., neither of these measure- 

 ments differing greatly from those of modern skulls. 



Only in Spy cranium No. 1 can the dimensions of the 

 orbit be calculated. Transversely the orbits of that skull 

 measure 40 m.m., and vertically 38 m.m., proportions which 

 are in no way peculiar. 



The inter - orbital breadth is, in the Neanderthal 

 skull, 30 m.m.; in Spy cranium No. 1, 30 m.m.; No. 2, 30 

 m.m.; in Australian skulls, ..from 22 to 28 m.m:; in negro 

 skulls, frequently over 30 m.m.; in European skulls, fre- 

 quently over 25 m.m.; in adult gorillas, from 24 to 28 m.m.; 

 in chimpanzees, 22 to 26 m.m.; and in orangs, commonly 

 under 20 m.m. The inter-orbital breadth depends to some 

 extent upon the development of the upper turbinate bones, 

 which in turn depend upon the degree in which the sense 



1 Cunningham and Telford Smith, "The Brain and Cranium of a 

 Microcephalic Idiot," Trans. Roy. Dub. Soc, vol. v., pt. via., p. 340. 



2 Humphry, "Notes on Nineteen Microcephalic Skulls," Journ. Anat. 

 and Physiology Feb., 1895. 



