April, 1922 unhindered growth of the incisor 171 



The right lower incisor was crowded between the left lower 

 incisor and the bones of the left side of the face. It shows the 

 effect of pressure and also that it was rubbed between its mate 

 and the skin of the face. The hair on the face is worn very close 

 along the line of this tooth also. Unfortunately since it was 

 broken across when the animal was killed, no more accurate 

 information can be had as to its position. The photograph 

 shows it ending freely over the part of the left lower tooth 

 which disappears into the head. 



The stump of the right upper incisor is shown on the animal's 

 right. The tooth is curving sharply and if the part broken off 

 could be found it might show that the point was nearly as high 

 as those of the teeth on the lower jaw. 



d. i. dx. — Right upper incisor (broken off). 



d. i. s. — Left upper incisor which passes down the animal's throat. 



e. s. — Left eye socket through which the lower incisor plowed. 



V. i. dx. — Right lower incisor (broken off but placed about as it must have been 



in life). 

 V. i. s. — Left lower incisor penetrating the skull and brain. 



The left upper incisor turns directly down and back into the 

 mouth and, according to the man who mounted the head, 

 extended down the throat for more than an inch. 



This case is a fine example of the way rodent chisel teeth 

 with persistent pulps (or with continuous growing germs) act 

 when for any reason the wearing of the teeth is hindered. iThe 

 fate that follows is inexorable and starvation is its logical end. 



How^ did the animal get any nourishment at all? The bodies 

 of the upper and lower incisors firmly fixed side by side seem to 



