EXPLANATION OF PLATE XVI. 



All the figures of the natural size, except Figs. 13-17. 



Pigs. 1-6. Anosteira ornata: 



Fig. 1. Portions, of the carapace. 



Fig. 2. Portion of the same specimen, with portions of the plastron. Specimens collected 



by Dr. Carter in the vicinity of Fort Bridger. 

 Fig. 3. Inner view of three costals, from a portion of the same specimen as Fig. 1, exhibiting 



the costal capitula. 

 Fig. 4. A third marginal plate from a larger individual. Dr. Carter. 

 Fig. 5. A fourth marginal plate of the left-side of another individual. From Washakia ; 



collected by James Stevenson. 

 Fig. 6. Section of a pygal plate. From a specimen found by Professor Hayden at Church 



Buttes. 

 Fig. 7. Ilium of a turtle. Obtained at Grizzly Buttes by Dr. Carter. 



Figs. 8, 9. Baena arenosa : 



Fig. 8. Ilium of the right side, outer view. Fig. 9. Sacrum, inferior view. Specimens ob- 

 tained from portions of the matrix, pertaining to the specimen of the shell represented in 

 Figs. 1, 2, Plate XIII. 



Fig. 10. Opisthocoelian caudal vertebra of a turtle. From near Lodge-pole trail. Dr. 

 Carter. 



Fig. 11. Fragment of a costal plate of a trionyx. From near Fort Bridger. Dr. Carter. 



Fig. 12. Fragment of a costal plate of a trionyx. From Little Sandy Creek. Professor 

 Hayden. 



Figs. 13-17. Glyptosaurus. All magnified two diameters. 



Figs. 13-15. Osseous dermal plates of the body. Figs. 16, 17. Plates of the head. From 

 Grizzly Buttes. Dr. Carter. 



Figs. 18, 19. Oligosimus grandee vus : 



Fig. 18. Posterior view of a caudal vertebra. Fig. 19. Lateral view. Specimen obtained 

 by Professor Hayden's party on Henry's Fork of Green Eiver. 



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