CHELONIA. 613 
Order CuEtonia. Tortoises and Turtles 
GENERAL CHARACTERS.—TZhe broad trunk is encased in 
bones which form a dorsal and a ventral shield, within the 
Fic. 330.—Skull of turtle. 
§.0O., supra-occipital; PAR., parietal; #R., frontal; P.F., pre- 
frontal; PO.F., post-frontal; SQ., squamosal; PALX., pre- 
maxilla; M2X., maxilla; /., jugal; Q./., quadrato-jugal ; Q., 
quadrate; D., dentary; AW., angular; AR., articular; S., 
surangular. 
shelter of which the head and nech, tail and limbs, can be 
more or less retracted. The dorsal carapace ts usually formed 
