5 8 4 



REPTILES. 



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 membrane bones 

 — dentary, splenial, coronoid, angular, and surangular. 



The hyoid region is very simple. 



mx 



Fig. 254. — Crocodile's skull from dorsal surface. 



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

 tal ; /., jugal ; p./., postfrontal ; q.j., quadrato-jugal ; y., 

 quadrate; sq., squamosal; pa., parietal; e.pt., epipterygoid ; 

 f., frontal ; pt. t pterygoid (on lower surface); o.t., os trans- 

 versum (on lower surface) ; »., nasal. 



The pectoral arch includes a dorsal scapula and a. ventral coracoid 

 (with a characteristic foramen) ; there are no clavicles nor epicoracoids, 

 but there is a sternum and a so-called interclavicle or episternum ; the 

 fore-limb is well though not strongly developed ; there are five digits, 

 webbed and clawed. 



In the pelvic arch, large ilia are united to the strong ribs of the two 

 sacral vertebrae : the pubes, or more strictly the epipubes, slope for- 



