408 



CHELONIA. 



therefore incomplete. The cohimella auris is bony and reaches 

 from the fenestra ovahs to a small cartilage in the tym- 

 panum. In the mandible, the two dentaries are fused, as in 

 birds, and five pairs of other bones are present (articular, angular, 



Fig 22'). Skeleton of Emys europaea, in ventral view v.ith plastron turned to one side 



(fro"!!! Clans). B plastron ; C costal plates ; CI epiplastron (clavicle) ; Co coracoid; F fibula ; 

 Fe femur ■ H humerus ; J cl entoplastron (interclavicle) ; Jl ilium ; Js ischium ; il/ marginal 

 plates • Nu nuchal, Py pvgal plate ; Pb pubis ; Pco precoracoid (acromial process) ; R 

 radius'; Sc scapula ; T tibia ; V ulna ; V neural plates. 



surangular, splenial, and coronoid). The hyoid consists of a 

 cartilaginous basilingual plate and of two pairs of ossified cornua, 

 which have no direct connection with the skull. 



Teeth are completely absent, but the jaws, both upper and 



