TAB. XVI. 



Trionyx Henrici. 



Fig. 



1 . Upper view of the carapace, wanting the nuchal plate, half nat. size. 

 si — s-j. The first to the seventh neural plates inclusive. 



pl\ — ph. The eight costal plates of the left side. 



2. Outline of the transverse curvature of the upper surface of the carapace. 



3. The nuchal plate of probably the same species of Trionyx ; but of another 



individual : half the natural size. 



