PLATE 8. 
Chelone planiceps, nat. size (from Portland stone). 
Fig. 
. Front view of skull. 
. Side view. 
a. Premaxillary. 
4. Maxillary. 
c. Nasal (here distinct from). 
di. Prefrontal. 
d. Frontal. 
. Top view. 
do. Postfrontal. 
Chelone pulchriceps, nat. size (from chalk). 
4. Side view of skull. 
5. Top view: the letters indicate the same bones as in figs. 2 and 3. 
6. Base view- 
7. Top view of the skull of a recent Chelonian (Hydromedusa, Wagler), with the 
nasals (c) and prefrontals (di) distinct, as in the fossils. 
