EXPLANATION OF PLATE 7. 



Figs. 1 and 2. Acrodus oreodontus, n. sp. No. 10251. Middle Triassic, Cot- 

 tonwood Canon, West Humboldt Eange, Nevada. X 1J. 



Fig. 3. Hybodus nevadensis, n. sp. No. 10254. Middle Triassic, Cotton- 

 wood Canon, West Humboldt Eange, Nevada. X 2. 



Fig. 4. Hybodus shastensis, n. sp. No. 10255. Upper Triassic, Bear Cove, 

 Shasta County, California. X 2. 



Figs. 5 and 6. Acrodus alexandrae, n. sp. No. 9874. Middle Triassic, 

 Fisher Canon, West Humboldt Eange, Nevada. X 1. 



