332 COMPARATIVE ANATOMY AND PHYSIOLOGY. 



ossifications. In Birds these fuse with one another 

 and with the supra- and ex-occipital bones to an 



MES 



Fig. 140. Diagram of the Cranial Bones of a Mammal, showing the 

 Foramina of exit of the several Cerebral Nerves.* 



1, Olfactory nerve ; 2, optic ; of, optic foramen ; flu, foramen lacerum anteriuni, for 

 the passage of the third, fourth, sixth, and first branch of fifth ne r ve (3, 4, 

 6, 5o.j ; fr, foramen rotundum, for the second branch of the fifth (5/3) ; fo, 

 foramen ovale, for the third branch of the fifth (5y) ; smf, styloiriastoid 

 foramen for the seventh nerve (7) ; flp, foramen lacerum postering, for the 

 ninth, tenth, and eleventh nerves ; MES, mesethmoid ; c/, condylar foramen 

 for the twelfth nerve ; CP, cribriform plate : PS, presphenoid ; BS, basi- 

 sphenoid; BO, basioccipital ; os, orbitospuenoid ; AS, all sphenoid ; EO, ex- 

 occipital ; PER, periotic ; FH, froutals ; PA, parietals ; so, supraoccipital. 



extent of completeness which is greater than ordinarily 

 obtains among Mammals. 



In addition to the important relations which the 

 cranium bears to the sense capsules, it has others even 



* This diagram was, many years ago, shown to the author by 

 Prof. Flower, F.R.S., and it is here, for the first time, published 

 by his kind permission. 



