TAB. XII. 



Fig. 



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



Crocodilus biporcatm. 



2. The same part of Crocodilus Mastiiigsia. 



3. The same part of Alligator niger. 



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

 "). The same? part of Crocodilus Hasting sire. 



6. The same part of Alligator niger. 



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



