CHELONIDAE 



and costal shields is strongly keeled, the three rows of keels 

 converging towards the posterior end of the shell. The neural 

 series of keels is almost continuous, and remains longest, even in 

 half-grown specimens. The twelve pairs of marginal shields form 

 at first a strongly serrated sharp edge ; the serrations disappear 

 gradually on the front portion, but remain on the posterior half 

 of the shell. The horny covers of the jaws form a hooked beak, 

 with sharp but smooth or feebly denticulated margins. The fore- 



Fig. 86.— Chelone imbricata. (" HawksMl Turtle "), yoiing. x J, 



and hind- flippers have two claws. The young are pale brown 

 above, blackish below; the shell of the adult is beautifully 

 marbled with yellow on a rich dark-brown ground ; the plastron 

 is yellow. The shields and scales of the head and limbs are dark 

 brown, with yellow margins. The top of the head is covered by a 

 large unpaired frontal and a pair of prefrontal or interorbital shields. 

 This Turtle does not reach the size _ of the green or edible kind ; 

 the largest shell on record is in the National Collection, and 

 measures 85 cm. = 34 inches in length. They range over all the 

 tropical and subtropical seas. They are apparently strictly car- 

 TOL. viii 2 c 



