in MAMMALIAN SKULLS. 195 



of the line gh to that of ah taken as 100, in the three 

 skulls, is as follows: — Beaver, 70 to 100; Lemur, 119 to 

 100; Baboon, 144 to 100. In an adult male Gorilla the 

 cerebral length is as 170 to the basicranial axis taken 

 as 100, in the Negro (Fig. 30) as 230 to 100. In the 

 Constantinople skull (Fig. 30) it is as 2G6 to 100. The 

 difference between the highest Ape's skull and the lowest 

 Man's is therefore very strikingly brought out by these 

 measurements. 



In the diagram of the Baboon's skull the dotted lines 

 d 1 (P, &c., give the angles of the Lemur's and Beaver's skull, 

 as laid down upon the basicranial axis of the Baboon. The 

 line a b has the same length in each diagram. 



slightly acute angle with this " basicranial axis/' 

 while the plane of the tentorium (i T) is inclined 

 at rather more than 90° to the " basicranial axis "; 

 and so is the plane of the perforated plate (a d), 

 by which the filaments of the olfactory nerve 

 leave the skull. Again, a line drawn through the 

 axis of the face, between the bones called ethmoid 

 and vomer — the " basifacial axis " (f. e.) forms an 

 exceedingly obtuse angle, where, when produced, 

 it cuts the " basicranial axis." 



If the angle made by the line b c with a b, be 

 called the " occipital angle," and the angle made 

 by the line a d with a & be termed the " olfactory 

 angle " and that made by i T with a b the " ten- 

 torial angle y then all these, in the mammal in 

 question, are nearly right angles, varying between 

 80° and 110°. The angle e f b, or that made by the 

 cranial with the facial axis, and which may be 

 termed the " craniofacial angle," is extremely ob- 

 tuse, amounting, in the case of the Beaver, to at 

 least 150°. 



