380 



suture between nasal and frontal bones was lying on the forehead 

 at the spot where in man not seldom tlie so-called Fonlicnlns 

 metopicMis is sitnated. The resnlts of the enibryological research lend 

 support to tiiis view. 



Another phenomenon explaine<l b\ this transference of the insertion 

 of the membranons vault on the nasal capsule is the intra-orbital 

 sitnation of the entrance to the lacrimal dnct. In the half-apes this 

 opening is extra-oi-bital ; in the apes, on the other hand, it is taken 

 up in the medial wall of the orbit together with the os lacrjmale, 

 in consequence of the shortening of the facial part of the sknll in 

 this region. 



It appears then that through this transference of the insertion 

 of the membranons vault to the anterior surface of the nasal capsule 

 in consequence of the intense development of the cerebral hemis- 

 pheres, we are able to inter[)ret in a simple way three apparently 

 heterogeneous phenomena, viz. Crista galli, Fonticulus metopicns, 

 and intraorbital position of the lacrimal foranien. In this connection 

 1 may still add a remark about the other Primates. We have stated 

 that apes, however much their jaws may project, possess iji reality 

 an orthognathous skull like that of man; they are to be classed as 

 pseudoprognathons. The persistence of the subcerebral position of 

 the nasal cavity, also in. apes, is the reason why the human 

 physiognomy is ever more or less discernible in apes, which is to 

 be ascribed chiefly to the position of the eyes. Originally the eyes 

 of all mammalian embryos are disposed on the lateral surface of 

 the head. In the prognathous type, in which the nasal cavity rotates 

 before the cranial cavity the eyes retain their lateral position. In 

 the orthognathous type, on the contrary, in which the nasal cavity 

 persists under the cranial cavity the eyes can draw nearer to each 

 other, and instead of the nasal cavity the orbitae occupy a precerebral 

 position. Now this rotation obtains with all Primates, and this is 

 why, physiognomically, apes resemble man. 



In conclusion another point of similarity is the fact that all 

 Primates possess a Crista galli, so in all of them the insertion of 

 the membranous vault of the crane is transferred to the nasal capsule 

 under the influence of the intense growth of the cerebral hemispheres, 

 which is proved also by the intraorbital position of the foramen 

 lacrymale in this class of mammals. 



