12 



CHELONIA. 



present, as in the type of T. incrassatus. The neural 

 region of the carapace is depressed. The vertebrae remain 

 on the ventral aspect. PvrcJiased, 1859. 



Fig. 3. 



Trionyx (cf.) gergensi. — Carapace ; from the Lower Miocene of the Mayence 

 basin. A The fourth right costal with the sculpture is shown on a larger 

 scale below, nu, nuchal. 



Trionyx parlsiensis, Meyer \ 



Known only by a single costal bone, which has a fine sculpture, 

 and is of considerable thickness, with the free margin abruptly 

 truncated. One of the Hordwell forms may be identical with this 

 species. 



1 Paheologica, p. 101 (1832). 



