EXPLANATION OF PLATE 6. 



CymbospondiilnR petriium Leidy. 

 From the Middle Triassic of West Humboldt Rane, Nevada. 



Figr. 1. Lateral view of cranium, no. 9913, about J %(>< of natural size. 



Fifj. 2. Anterior view of cranium, no. 9950, a little less than % of natural size. 



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