Vol. 69.] SKULL EKOH riLTDOWN. 147 



excavation of the temporal area, to form the wide bay between the 

 inferior temporal pole and the cerebellum. This is clue to the 

 marked attenuation of the temporal region ; but, as we have already 

 seen in the case of the parietal region, so also here are definite 

 signs tbat the expansion has begun which eventually will trans- 

 form this area into the very different configuration that it presents 

 in the modern brain. There is a very prominent elliptical swelling, 

 the summit of which (at T) is raised more than a centimetre above 

 the level of the surrounding cortex. It is 2 centimetres in vertical 

 measurement and almost 3 centimetres long. This peculiar con- 

 formation assumes quite a special interest when it is remembered 

 that this obviously expanding area occupies the position where in 

 the modern human brain is developed the territory which recent 

 clinical research leads us to associate with the power of 'spon- 

 taneous elaboration of speech and the ability to recall names ' 

 (Adolf Meyer). 



The configuration of the anterior part of the temporal area is 

 also peculiar, though a suggestion of the same kind of form is seen 

 in the Gibi^altar brain-cast. Below the point marked I the surface 

 slopes inwards towards the mesial plane, so that the fulness of the 

 temporal pole of the modern brain is wanting. 



There is marked asymmetry of the cerebellum and of the occi- 

 pital poles of the cerebrum. 



Taking all its features into consideration, we must regard 

 this as being the most primitive and most simian 

 human brain so far recorded; one, moreover, such as might 

 reasonably have been expected to be associated in one and the 

 same individual with the mandible which so definitely indicates 

 the zoological rank of its original possessor. 



The apparent paradox of the association of a simian jaw with 

 a human brain is not surprising to anyone familiar with recent 

 research upon the evolution of man. In the process of evolving 

 the brain of man from the ape the superficial area of the cerebral 

 cortex must necessarily be tripled ; and this expansion was not 

 like the mere growth of a muscle with exercise, but the gradual 

 building-up of the most complex mechanism in existence. The 

 growth of the brain preceded the refinement of the features and 

 of the somatic characters in general. 



Discussion. 



Sir Hay Lankester congratulated the Authors on the very clear 

 and interesting account given by them of their important discovery. 

 Two distinct questions arose in regard to the bones discovered : 

 first, what are the characters of skull and jaw indicated, and, 

 secondly, what is the geological age of the specimens ? He had 

 been allowed to examine the jaw and skull some weeks ago, and 

 with Mr. Dawson had visited the locality where they were found. 

 In regard to the zoological characters of the individual indicated by 

 the bones — everything depended on the little projecting piece at the 



