The Biology of the Crocodilia 5 
odilia may well form an aquatic, further developed 
branch” (Cambridge Natural History, p. 432). 
Skull of Belodon. A, from above; B, from below. A, orbit; Bo, 
basi-occipital; Ch, internal nares; D, pre-orbital fossa; Exo. exocci- 
pital; Fr. frontal; Ju. jugal; La. lacrymal; Mx. maxilla; Na. nasal; 
Pa. parietal; Pl. palatine; Pmx. pre-maxilla; Por. post-orbital; Prf. 
pre-frontal; Pt. pterygoid; Qu. quadrate; S, lateral temporal fossa; 
S', superior temporal fossa; Sg. squamosal; Vo. vomer. (From Zittel.) 
Fic. A. A Triassic ANCESTOR OF THE CROCODILIA, 
From Parker & Haswell, Textbook of Zodlogy. 
The direct ancestors of the Crocodilia, Gadow 
says, are still unknown. 
