EXPLANATION OF PLATES. 
PcAwr ele 
Labidosaurus hamatus Cope. Skull, from above; two-thirds natural size. 
PrArh ial: 
Labidosaurus hamatus Cope. Fig. 1, skull, from below; two-thirds natural 
size. A, articular; AN, angular; BS, basisphenoid; HP, epiotic; EX, exoc- 
cipital; PP, postparietal; PT, pterygoid; Q, quadrate; ST, stapes. 
Labidosaurus hamatus Cope. Fig. 2, skull, from the side; two-thirds nat- 
ural size. 
PLATE III. 
Labidosaurus hamatus Cope. Fig. 1, right quadrate, from below; Fig. 
2, the same, from above; Fig. 3, posterior basicranial bones from above; 
Fig. 4, skull, from behind. All two-thirds natural size. EP, epiotic; EPT, 
epipterygoid ; OC, occipital condyle; PO, paroccipital; PP, postparietal; PR, 
proétic; PT, pterygoid; Q, quadrate; SO, supraoccipital. 
