TAB. XII. 



Fig. 



1. Upper surface of the symphysial end of the right ramus of the lower jaw of 



Crocodilus biporcatus. 



2. The same part of Crocodilus Hastingsice. 



3. The same part of Alligator niger. 



4. The hinder part of the right ramus of the lower jaw of Crocodilus biporcatus. 



5. The same part of Crocodilus Hasting sice. 



6. The same part of Alligator niger. 



Figures 1, 2, 4, 5, two-thirds, 3 and 6 one half the nat. size. 



