( 375 ) 
for adult and juvenile skulls. The proof is here more stringent because 
of the larger number of juvenile skulls of which the basal index 
was determined. For the adult skulls I obtained the following figures: 
69, 65, 60, 60, 58, 58 and for the juvenile ones 55, 53,51,51,50. 
In tig. 4 the mediagrams of a juvenile and an adult skull have again 
been superposed. The former had still all its milk teeth. 
For Gorilla finally I refer fo Fig. 5 in which the mediagram of 
an infantile gorilla skull with complete milk teeth has been drawn 
on that of an adult skull. We state the same-phenomena as with the 
=*- 
Fig. 5. 
Mediagrams of an adult and an infantile skull of Gorilla, 
remaining Anthropoids: lengthening of the cranial base and diminished 
vaulting of the occipital are here also met with. As to the basal 
