EXPLANATION 



OF PLATE 16. 



Thinohyus (Bothrolabis) decedens Cope. Cranium and mandible from the 

 left side. X%. Two specimens are combined in the drawing 

 (Cranium No. 556 and mandible No. 1989). P 1 should not 

 extend beneath the level of P". The anterior nasal region 

 has been restored in the figure. 



