EXPLANATION OF PLATE V. 



Figs, i and la. Triconodon ? bisulcus Marsh (Atlantosaurus beds), left upper 



molars, m 2 and m 3 , crown and external views. Six times natural size 



(No. 269SU. S. N. M.). 

 Figs. 2, 2a and 2b. Dryolestes sp. (Atlantosaurus beds), left upper molars; 



crown, external, and posterior views. Seven times natural size (No. 



2845 U. S. N. M.). 

 Fig. 3. Dryolestes, first right upper molar, m 1 ; crown view. Eight times natural 



size (No. 2S39 U. S. N. M.). 

 Figs. 4 and 4a. Dicrocynodon sp. (Atlantosaurus beds), left upper molars; 



crown and external views. Six times natural size (No. 2715 U. S. N. 



M.). 

 Figs. 5, 5a, 5^ and 5c. Paurodon sp. (Atlantosaurus beds), right lower molar, 



m 2 , crown, external, internal and posterior views. Eight times natural 



size (No. 2733 U. S. N. M.). 

 Figs. 6, 6a, 6b and 6c. ? Pediotnys sp. (Laramie beds), left upper molar; crown, 



external, posterior, and anterior views. Eight times natural size (No. 



5062 U. S. N. M.). 

 Figs. 7, "ja and "jb. Gen. et sp. indt. (Laramie beds), left upper molar; crown, 



external and anterior views. Eight times natural size (No. 5076 U. S. 



N. M.). 



