PATAGONIAN EXPEDITIONS ! PALEONTOLOGY. 
Figs. I- 
Fig. 6. 
EXPLANATION OF PLATE XVI. 
PAGE 
. Nesodon imbricatus : Stages in development of the upper in- 
cisors, from specimens in the Ameghino 
collection. Anterior view. . . . 119 
“ “ Upper incisors of an animal past maturity. 
Type of JV. marmoratus, La Plata 
Museum. . . . . . . 138 
All figures natural size. 
(VOL. VI.) 
