SKELETAL SYSTEM. 



637 



the mouth, covering the vomers, and determining the position of the 

 posterior nares at the very back of the mouth ; an os transversum or 

 transpalatine extends between the maxilla and the junction of palatine 

 and pterygoid ; a postorbital rod (epipterygoid or columella) is formed 

 by a downward process of the postfrontal meeting an upward process 

 from the jugal ; the quadrate is large and immovable ; there are large 



p.jnx 



FIG. 350. Crocodile's skull from dorsal surface. 



p.mx.) Premaxilla ; rnx., maxilla; /., lachrymal; pr.f., prefron- 

 tal ; j. t jugal; P*f. t postfrontal; g.j., quadrato-jugal ; g. t 

 quadrate ; .r^., squamosal ; pa. , parietal; e.pt.^ epipterygoid J 

 f. t frontal; />/., pterygoid (on lower surface); <?.*., os trans- 

 versum (on lower surface) ; ., nasal. 



parotic processes ; the tympanic cavity is completely bounded by bone ; 

 the teeth, which are borne by premaxillae, maxillae, and dentaries, are 

 lodged in distinct cavities ; beside and eventually beneath the teeth lie 

 reserve " germs" of others. 



Each ramus of the mandible consists, as in most Reptiles, of a 

 cartilage bone the articular working on the quadrate, and five 



