43 



Family II. ELODITES.* 



CHARACTERS. 



1. The shell is always solid, more or less depressed, and covered with horny 



plates, of which there are thirteen dorsal, and from twenty-three to twenty- 

 five marginal. 



2. The sternum is solid, never longer than the shell; it varies in form, and in 



its mode of union with the carapace; in some (Emys) it is solidly united; in 

 others (Chelonura) it is joined by cartilage; it is always covered with horny 

 plates, varying in number from eight to thirteen. 



3. The head diflcrs much in size and form, in different senera. 



4. The eyes may be lateral or not. The two eyelids are nearly of the same 



extent, and open obliquely downwards and forwards. 



5. The tongue is shorter, thinner, and less fleshy than in Chersites. 



6. The jaws vary in form; and their cutting margins may be simple, or more or 

 less serrated. 



7. The tympanum is visible. 



*Eaoc; e^owfit. Palus; palustris. 



