176 THE GENERAL ANATOMY OF GORILLA [SECT. A 



The lumbar centra are vertically higher and transversely 

 narrower than those of Man. While the lateral and mammil- 

 lary processes are well developed, the accessory is insignificant. 

 Anapophyses are not seen, but sometimes they occur in the 

 Orang-utan. 



The " transverse " process of the third lumbar vertebra is small 

 in comparison with the others and thus differs from its repre- 

 sentative in Man. The interlocking of the vertebrae, brought 

 about by the superior articular processes of one vertebra em- 

 bracing the lower processes of the vertebra above, is much less 

 effective and complete than in Man ; for the former processes 

 do not extend so far round the latter as in Man and their 

 hold is correspondingly more feeble. The two forms are represented 

 in Fig. 117. The differences between the vertebral columns of 

 Man and Gorilla are extraordinarily well marked in this region, 

 which is profoundly modified in correspondence with the difference 

 between the erect attitude of Man and the crouching one of the 

 anthropoid ape. 



The sacrum (Fig. 118) of the Gorilla consists usually of six pieces; 

 the laminae of these unite posteriorly with remarkable constancy 

 and regularity : the variety of spina bifida which consists of a lack 

 of union of these laminae is thus of infrequent occurrence. A well- 

 marked sacral notch is usual, and is due to the comparative 

 attenuation of the second sacral vertebra 1 . The coccyx is rudi- 

 mentary as in Man. The sacral index is stated by Turner to be 

 72 (Homo 112): and the curvature is small, the average depth of 

 the sacral curve being 104 mm. (Paterson) as against 251 mm. 

 in the (white) Hominidae. 



A general review of the characters of the vertebral column 

 shews that the Gorilla differs from Man in respect of the degree 

 of anterior lumbar curvature (Fig. 118). As regards the vertebral 

 foramina, these are throughout more circular in outline than in Man ; 

 nor as regards the centra of the vertebrae does the Gorilla shew in 

 the cervical and lumbar- regions the marked excess of (he transverse 

 over the sagittal diameter so characteristic of the corresponding 

 human vertebrae. In fact, the vertebral column of the Gorilla 



1 Cf. Paterson, The Human Sacrum, p. 132. 



2 The specimen shewn in Fig. 117 (A) does not conform to this statement. 



