SKULL 



119 



The parietals and frontals are unpaired in the adult, and lacrymaLs, 

 prefrontals, and postfrontals are present. There is an upper and 

 a lower temporal arcade or zygomatic arch, and between the orbit 

 and temporal fossa is a bony pillar formed by the postfrontal, jugal, 



FIG. So. HYOBRANCHIAL APPARATUS, 

 WITH LARYNX AND TRACHEA, OF 

 Emys curoptt'a. From the dorsal 

 side. 



.4 A', arytenoid cartilage 

 Cbr.I, 6V.//, first 

 branchial cornua; Chi/, 

 P.I, lingual process ; 

 cartilage of larynx ; 

 ZB, broader anterior, 

 rower posterior part 

 branchial. 



of larynx ; 



and second 

 hyoid cornu ; 



RK, cricoid 

 Tr, trachea ; 

 and ZK, nar- 



of basihyo- 



Coce 



FIG. 86. SKULL OF A YOUNG 

 CROCODILE. Ventral view. 



Ch, internal nostrils ; Coce, oc- 

 cipital condyles ; J<j, jugal ; 

 J/, palatine process of max- 

 illa ; Ob, basioccipital ; Orb, 

 orbit ; PI, palatine ; Pmx, 

 premaxilla ;. Pt, pterygoid ; 

 >.>/, paraquadrate ("quadrato- 

 jugal"); (Jit, quadrate; Ts, 

 transpalatine. 



and transpalatine : the vomer is paired. The palatines and ptery- 

 goids are very firmly attached to the base of the skull, and both 

 these bones, as well as the paired premaxilke and maxillae, take 

 part in the formation of the hard palate. 1 Thus the internal 

 nostrils open far back, beneath the basioccipital, from which alone 

 the occipital condyle is formed. The exoccipitals meet above the 

 foramen magnum, thus shutting out the supraoccipital. Teeth are 

 present in sockets on the premaxillae, maxillae, and dentaries. 



A series of air-passages extends into the bones from the 



1 In the pre-Cretaceous Crocodiles the pterygoids did not form palatal 

 plates. 



,** 



