130 
POPULAR SCIENCE REYIEW. 
US with a parallel diversity, though the head and jaws are 
about equally developed in all of them. These spines are 
quite short in Loris and Nycticebus, while they'are prodigiously 
long in Perodicticus and Arctocebus. 
Pig. 14. 
Skull of Orang. 
The skull of man presents in the frontal region an elevated 
and rounded contour, very different from what we find in the 
apes generally, and notably in the higher family of them. It is 
in the American forms — especially in Callithrix and Pithecia— 
