Vol. 69.] THE HUMAN SKULL, ETC. FROM PILTDOWN. 129 



•Chatham Islands (Brit. Mus. 91.1.20.1). The mastoid portion has no 

 conspicuous extension on the occipital plane, and though its process 

 (mast.) is rather small, this is of the characteristic shape and 

 relations, with a deep impression on its inner side for the origin of 

 'the digastric muscle. The supramastoid ridge on the outer face 

 behind the malar arch is an irregularly-rounded boss. The malar 

 arch (mal.) arises in the usual form from the squamous part of 

 the bone, and the glenoid cavity (gl.) is as deep as the deepest 

 observable in modern man, with a transversely-extended hollow 

 ■at the bottom slightly overhung by the anterior ginglymoid surface. 

 There is no ' spina gienoidalis,' such as is described by Prof. Boule 

 an the Mousterian skull from La Chapelle-aux-Saints. 1 A distinct 

 though small postarticular process (p.a.p.) occurs, separating the 

 upper part of the tympanic from the glenoid cavity ; and the long 

 axis of the ovoid opening of the external auditory meatus (e.a.m.) is 

 inclined downwards and backwards as in modern man, not forwards 

 as in the Mousterian man from La Chapelle-aux-Saints.- The 

 base of the styloid process (st.) proves it to have been very small. 

 The petrous portion of the bone exhibits all its characteristic 

 features, with no peculiarity worthy of remark ; and the cerebral face 

 •of the mastoid bears the usual broad deep groove for the lateral 

 sinus (si.). The maximum horizontal extent of the temporal bone 

 is 95 mm., and the greatest depth of its squamous wing above 

 the auditory meatus is 57 mm. ; while its maximum thickness 

 at the parieto-mastoid suture is no less than 14 mm. 



The various measurements of the parts of the skull already given, 

 and some others that are also of importance, may be conveniently 

 tabulated as bekrw (p. 130), for comparison with the corresponding 

 measurements of the skulls from Gibraltar and La Chapelle-aux- 

 Saints. 



The right mandibular ramus (PI. XX, figs. 2, 2a, 2 b, & 2 c) is 

 in the same mineralized condition as the skull, and corresponds 

 sufficiently well in size to be referred to the same specimen without 

 any hesitation. It lacks the articular condyle and the upper part of 

 the bone in advance of the molars; but it is otherwise well preserved, 

 and still exhibits the first two molars in their sockets. Its outer 

 face is sufficiently disintegrated to show the direction of the con- 

 stituent fibres of the bony tissue. The ascending portion, as in the 

 mandibles from Heidelberg and La Chapelle-aux-Saints, is relatively 

 broad, its width just below the sigmoid notch being 45 mm. ; while 

 its depth at the coronoid process (cor.) is about 70 mm. As in the 

 same jaws, its hinder margin makes an angle of 110° with the inferior 

 margin, its sigmoid notch is comparatively shallow, and the neck of 

 its articular condyle (cd.) must have been short. The bone itself is 

 thin, and its outer face is deeply impressed with irregular hollows for 



1 Ann. de Paleont. vol. vi (1911) p. 58. 



2 Ibid. pp. 44, 54. 



•Q. J. G. S. No. 273. k 



