12 FOSSIL CHELONIAN REPTILES. 



Platemys DixoNi. Owen. Table IX, fig. III. 



A platemydian specifically distinct from either of the above is more unequivocally 

 exemplified by the sternal element represented in Tab. IX, fig. Ill, the matrix having 

 been carefully removed from the outer surface of this fossil, the linear impressions 

 which have divided the humeral from the pectoral scute, and this from the abdominal 

 scute, are clearly shown. The positions of these transverse grooves accord with those 

 in the hyosternal of the Emydians, having the usual number (nine) of plastral elements : 

 and the hyosternal character of the fossil is further shown by the oblique border 

 cutting off the inner angle of the anterior end, for articulation with the entostemal 

 •element. (This end has been figured downwards in the plate.) The axillary groove 

 is narrower than in the above-described species ; and the whole bone seems to have 

 been longer in proportion to its breadth. It is from the Wealden of Til gate Forest, 

 and is now in the British Museum. I propose to dedicate the Wealden terrapene, 

 indicated by the above-described fossil, to my late esteemed friend, Frederic Dixon, Esq., 

 F.G.S., author of the beautiful work ' On the Cretaceous and Tertiary Formations 

 of Sussex.' 



