j 30 



ELEMENTAR Y ANA TO MY. 



[LESS. 



FIG. 117. Under Surface of the Cranium 

 of the Great Ant-eater (Myrmecophaga 

 jubata), ^. SO, supra-occipital ; BO, basi- 

 occipital ; ExO, exoccipital ; 7>, tym- 

 panic ; Pt, pterygoid ; Sy, squarnosal ; 

 AS, ali- sphenoid ; OS, orbito-sphenpid ; 

 M, malar ; L, lachrymal ; PI, palatine ; 

 MX, maxilla ; PMx, pre-maxilla. 

 {From Flower's "Osteology") 



parts of which it is made 

 up in man, the anterior 

 margin of the occipital 

 foramen forming, in the 

 immense majority, part 

 of the posterior boundary 

 of the inferior region. 



( i ) The anterior part ot 

 the basis cranii of man is 

 in him very exceptionally 

 short, both compared 

 with the middle or gut- 

 tural part, and compared 

 with its own width. Its 

 relative length varies of 

 course with the prolonga- 

 tion of the muzzle. Only 

 in Mammals and Croco- 

 diles can it be defined, 

 as in man, by the bony 

 palate formed as in him 

 by special developments 

 of the palatine and su- 

 perior maxillary bones. 

 Sometimes, as we have 

 seen, this part may be 

 augmented by the ptery- 

 goid bones also taking a 

 share in this structure, 

 as in the Great Ant-eater, 

 the Crocodiles, and Ce- 

 taceans. 



It is possible, how- 

 ever, as in the Hare, for 

 the bony palate to be 

 very little developed, or, 

 as in the Hedgehog, to 

 be only imperfectly ossi- 

 fied. The form and pro- 

 portion of its component 

 bones afford in Birds im- 

 portant characters for the 

 classification of different 

 groups. 



