51 



EMYS MEGACEPHALA. 



PlaU in. 



Characters. Shell suboval, flattened, carinate, serrated and acute posteriorly; 

 very dark brown, with obscure orange lines; sternum oblong, slightly emarginate 

 behind, dingy yellow; head very large; jaws entire. 



Description. The shell is suboval, slightly emarginate in front, serrated and 

 pointed behind, and flattened above, with a marked carina throughout its whole 

 extent. The vertebral plates are five in number; the first irregularly hexagonal, with 

 the posterior border curved and projecting into the anterior margin of the second 

 plate, which is also hexagonal, with its anterior margin excurved; the third and 

 fourth plates are hexagonal; the fifth almost semicircular in shape, and the part 

 representing the diameter of the semicircle is joined to four marginal plates. The 

 first lateral plate is triangular, with its basis rounded and connected with five 

 marginal plates; the second and third are hexagonal, with an acute angle above, 

 passing in between the vertebral plates; the fourth is pentagonal. Of the twenty- 

 five marginal plates, the nuchal or intermediate one is irregularly quadrilateral, 

 narrow before, broader behind, its posterior margin slightly excurved, for receiving 

 a small part of the first vertebral plate; the first marginal plate is pentagonal, 

 broadest in front; the remaining plates are quadrilateral; the fourth, fifth, sixth and 

 seventh, have revolute margins; the eighth, ninth, tenth and eleventh, have their 

 posterior and inferior angle lengthened, which gives the posterior margin of the 

 shell a serrated appearance; the two supra-caudal are elevated (en toit.) 



The sternum is oblong, entire in front, slightly emarginate and concave behind. 

 Of its twelve plates, the gular are very regularly triangular, having the apex of the 



