CHELONIID^E. CXVIII. 205 



FAMILY CXVIII. CHELONIHXE. (LOGGER-HEAD 

 TURTLES.) 



Sea turtles, with the carapace covered with bony plates ; carapace 

 heart-shaped, broad and flat, highest in front, widest near middle ; 

 head large, jaws without tooth-like projections. Genera 4; species 

 about 7, of the open sea, coming to shore only to deposit and bury 

 their eggs. 



a. Scales around large median plate on top of head 13 to 20; plates of carapace 

 not imbricate ; edge of lower jaw not serrate ; costal plates 5 on each side ; 

 scales on cheeks small, 15 to 20; head broad. . THALASSOCHELYS, 302. 

 aa. Scales around vertical plate 7; costal plates 4. 



b. Tomia of lower jaw not serrate; shields of carapace imbricated ; scales on 

 cheeks large, 7 to 10; head broad ...... ERETMOCHELYS, 303. 



bb. Tomia of lower jaw serrate; shields of carapace not imbricated; scales 

 on cheeks small, 15 to 20 ; head high and narrow. . CHELONIA, 304. 



302. THALASSOCHELYS Fitzinger. (0oXao-<ra, sea; 

 XeXv?, tortoise.) 



596. T. caretta (L.). LOGGER-HEAD TURTLE. Scales not 

 imbricate ; 2 nails to each foot. Atlantic, N. to Mass. ; reaches 

 450 Ibs. (Eu.) (An old name.) 



303. ERETMOCHELYS Fitzinger. (epcrpor, oar ; ^e Xvs.) 



597. E. imbricata (L.). TORTOISE-SHELL TURTLE. HAWKS- 

 BILL TURTLE. Jaws produced in a beak ; nails two. N. C. to 

 Brazil. Smaller and fiercer than the preceding, its scales used in 

 makin combs. 



304. CHELONIA Brongniart. (^eXon/i;, tortoise.) 



598. C. mydas (L.). GREEN TURTLE. Plates thin ; nail sin- 

 gle ; body oblong. L. I. to Brazil, herbivorous, reaching 850 Ibs., 

 and valued as food. (/*v8ao>, to be wet.) 



FAMILY CX1X. TRIONYCHID^J. (THE SOFT-SHELLED 

 TURTLES.) 



Body flat, nearly orbicular ; carapace not completely ossified, the 

 ribs projecting freely towards the outer extremities ; marginal ossi- 

 cles rudimentary ; carapace and plastron covered by a thick leathery 

 skin which is flexible at the margins. Head long and pointed, with 

 a long, flexible, tubular, pig-like snout ; neck long. Feet broadly 

 webbed ; toes long, 5-5, but the claws only 3-3. 



Aquatic, carnivorous and voracious ; species about 30, in both 

 hemispheres. 



a. Nostrils rather under the tip of snout; nasal septum without an internal 

 longitudinal ridge on each side ; head narrow ; edge of upper jaw serrate 

 behind .................. AMYDA, 305. 



