994 19. CHELONUDA 
eggs are spherical and very numerous, are inclosed in leathery 
shells, and when deposited in the pits are covered with sand 
and left by the turtle. 
Our knowledge of sea turtles is still too limited to justi- 
fy any very definite conclusions as to the number of species, 
or even very emphatic statements as to the difference or iden- 
tity of Atlantic and Pacific Ocean specimens. Still it seems 
best to regard those from the Pacific as distinct species. 
Synopsis OF GENERA 
a.—Carapace covered with thicker, horny, imbricate shields; 
pectorals and abdominals usually keeled; two pairs of 
prefrontal shields; costals four. 
Eretmochelys.—p. 994. 
a.—Carapace covered with thin, juxtaposed, shields; pector- 
als and abdominals usually smooth. 
b.—Vertebral plates five; costals four; one pair of pre- 
frontal shields. 
Chelonia.—p. 996. 
b.—Vertebral plates usually more than five or costals more 
than four; two pairs of prefrontal shields. 
Caretta.—p. 998. 
Genus 55. Eretmochelys 
Eretmochelys Frrzincrer, Syst. Rept., 1843, p. 30 (type, imbricata). 
Onychochelys Gray, Proc. Zool. Soc. Lond., 1873, p. 397, (type,O. 
hraussi). 
Shell covered with thick, imbricate, horny plates, the 
tortoise shell of commerce. Two pairs of prefrontal plates. 
Limbs large, paddle-shaped, with two claws. The verte- 
bral and costal plates are keeled in young, and the plastral 
plates in adults also. The marginals project making the edge 
of the carapace serrate. The beak is hooked like that of a 
hawk. 
