CHAP. V] THE CRANIA OF THE SIMIIDAE (PRIMATES) 233 



More recently three investigators 1 have published the results of 

 their studies on this and allied points, and they have confirmed 

 and extended the work of Professor Manouvrier. 



In the case of the human skull, this process of "correction" is not 

 nearly so evident as in those of some other animals, yet its existence 

 is undeniable. In the early stages, brain-growth proceeds with 

 so much momentum that it oversteps the mark. Then the mo- 

 mentum is gradually lost, thus favouring the action of other 

 agencies which make their appearance and become effective. 



,N, 



Fig. 157. Diagram illustrating differences in the inclination of the foramen 

 magnum (Op. B. ) to the middle portion (B. Pe.) of the cranial base. (Cf. Figs. 150 

 to 156 incl.) 



OP x . B.— B. Pp.. is the angle of inclination in the Dog. (Cf. Fig. 150.) 

 OP.,. B.— B. Pr. ,, ,, „ Child. 



OP3. B.— B. Pr. ,, ,, „ Adult Man. 



These effects are very striking in the skulls of young and of old 

 Gorillas, which have been studied by Professors Bolk and Keith 

 (op. cit). Again, the South American Howling Monkey (Mycetes) 

 is distinguished because the reversal goes to an extreme in this 

 instance (Leche 2 ). On the other hand it is suggested that the 

 process is non-existent in the small Chrysothrix monkey (also a 



1 Bolk, Koninklijke Akademie run Wetenschappen. Nov. '27, 1909; Dec. 24, 

 1909. Keith, J.A.P., Vol. xliv. Part 3, April 1910. Leche, Zoologisches Jahrbuch, 



Supplement xv, 2 Band, 1912. 



2 Leche, op. cit. 



