228 



CHELONIA. 



Family PROTOSTEGID^E. 



Carapace apparently represented merely by a row of marginals, 

 but the plastron very strongly developed and composed of thick 

 ossifications. Humerus (when known) with the radial process short, 

 blunt, and approximated to the head. Skull at present undescribed, 

 but, according to Baur \ approximating to that of the Chelonidce. 



The procoelous vertebras of the type genus,which were provisionally 

 regarded by Cope as dorsals and are described as showing indications 

 of transverse processes, are more probably referable to the cervical 

 region. The above interpretation of the structure of the shell is 



Fig. 52. 



Protosphargis veronensis. — Ventral aspect of the thoracico-abdoininal region ; 

 from the Upper Cretaceous of Italy. T y. (After Capellini.) 



based on the observations of Baur 2 , who regards the bones provi- 

 sionally referred by Cope to the carapace as plastral. In the form 

 from the Upper Cretaceous of Italy described by Capellini 3 as 

 ProtospJiargis (fig. 52), the humerus is unknown, and the ribs have 

 not the scaly expansions found in the type of Protostega. It has 



1 See note on p. 223. a Zool. Anzeig. vol. ix. pp. 087-689 (1886). 



3 Atti E. Ac. Line. ser. 3, vol. xviii. p. 291 (1884). 



