GENERAL NOTES ON SNAKES. 633 
Fic. 347.—Skull of grass-snake.—From W. K. Parker. 
A, Dorsal surface—fx., premaxilla; #zx., maxilla ; a#., external nostril ; #., nasal ; o/., 
nasal cartilages ; 4, prefronto-lachrymal ; ., parietal ; 7., frontal; da., palatine; 
z.pa., transpalatine; Jg., pterygoid; f70., pro-otic; ef., epiotic; of., opisthotic; 
so., supraoccipital ; ¢0., exoccipital ; av., articular ; s.ag., surangular ; ag., angular ; 
d.,dentary ; g., quadrate; sz.,squamosal. B, Ventral surface—fx., premaxilla; o., 
nasal cartilage; #z., maxilla ; v., vomer; Za., palatine; 4., parasphenoid; 7, frontal ; 
d/.,prefrontal; Zg., pterygoid; ds. ,basisphenoid; ads., alisphenoid; 5.0., basioccipital; 
oc.c., occipital condyle ; ¢o., exoccipital ; g., quadrate ; av., articular ; ag., angular ; 
S.ag., surangular ; ¢v., coronary ; sf., splenial ; @.,dentary ; of., opisthotic region, 
