66 SMITHSONIAN" MISCELLANEOUS COLLECTIONS VOL. 6l 



PLATE 20 

 (About l /& natural size) 



Illustrating age differences in female skulls. Skulls arranged by age, the 



youngest at the bottom. 



Angle of nasal boss increases with age, due to the production forward of the 



anterior border. Depth of the dorsal concavity grows less as age advances. 



Fig. i. Ceratotherium simum cottoni, female, old; from Rhino Camp, Lado 

 Enclave ; shot by Col. Theodore Roosevelt, January 29, 1910. 

 No. 164595, U. S. National Museum. 



Fig. 2. Ceratotherium simum cottoni, female, immature; last molar not yet 

 erupted ; from Rhino Camp, Lado Enclave ; shot by Col. Theodore 

 Roosevelt, January 10, 1910. No. 164587, U. S. National Museum. 



Fig. 3. Ceratotherium simum cottoni, female, immature ; last milk molars about 

 to be shed ; weathered skull ; from Rhino Camp, Lado Enclave. 

 No. 164599, U. S. National Museum. 



Fig. 4. Ceratotherium simum cottoni. female, immature; milk molars in use; 

 from Rhino Camp, Lado Enclave ; shot by Col. Theodore Roose- 

 velt, January 15, 1910. No. 164590, U. S. National Museum. 



