EXPLANATION OF PLATE XXVIII. 



Figs. 1, 2. UlNTATHEUIUM KOBUSTOM : 



Fig. 1. Outline talieu from Professor Marsh's Fig. 1, Plate II, of Dinoceras mirahilis, iu the 

 Am. Jour. Science, 1873, enlarged so as to accord with one-sixth of the size of the frag- 

 ments introduced iu the figure, which corresi^ond with those of Figs. 1 and 8, Plate XXV, 

 and Fig. 1, Plate XXVI. 



Kg. 2. View of the base of the cranial specimen also represented in Fig. 1, Plate XXVI. 

 One-sixth the diameter of nature. 



Fig. 3. Large osseous i>rotuberance, one-half the size of nature, resembling the similar 

 osseous protuberances of the specimen of Megaccrops, represented in Figs. 2, 3, Plate 1. 

 The specimen is from the Mauvaises Terres of White River, Dakota, and was originally 

 suspected to belong to Titanotherium. 



Figs. 4-8. Bison latifrons: 



Figs. 4, 5. Cranium from Pilarcitos Valley, California, discovered by Messrs. Calvin and 

 Wilfred Brown, and presented to the Academy of Natural Sciences of Philadeli^hia. One- 

 fifth the natur.al size. 



Fig. 4. Upper view. Fig. 5. Posterior view. 



Figs. 6, 7. The second and last npper molars seen on their triturating surfaces. Natural size. 

 Specimens from California, belonging to Wabash College, Indiana. 



Fig. 8. An upper second molar of the left side, considerably worn, and seen on its triturat- 

 ing surface. Natural size. From Luzerue County, Pennsylvania. 



Fig. 9. Mastodon americanxjs: 



A first lower premolar of the right side, natural size. Found with the iirecediug. 



