TRUE TEETH OF ORNITHORHYNCHUS. 231 
EXPLANATION OF PLATE VIII, 
Illustrating Professor Charles Stewart’s paper ‘On a Spe- 
cimen of the True Teeth of Ornithorhynchus.” 
a. Soft papilliform structure in front of true teeth of the right side of the 
upper jaw, the first or most anterior tooth having been shed. 
6. Second tooth of the right side, upper jaw. 
c. Third or posterior tooth of the right side, upper jaw. 
da. Papilla of left side, upper jaw. 
e. Socket for second tooth of left side, upper jaw. 
/- Socket for third tooth, left side, upper jaw. 
g- Deep surface of second tooth of left side, upper jaw, showing fangs. 
h. Deep surface of third tooth, left side, upper jaw. 
?. Second tooth of left side, upper jaw, viewed from posterior aspect. 
k. Socket for first or most anterior tooth of left side of lower jaw. 
1. Socket for second tooth, left side, lower jaw. 
m. Socket for third tooth, left side, lower jaw. 
n. First or most anterior tooth of right side of lower jaw in situ. 
o. Second tooth of right side, lower jaw, in situ. 
p. Third or most posterior tooth, right side, lower jaw. 
q, 7, 8. Deep surface of first (¢), second (r), and third (s) teeth of left side. 
The crowns of the teeth of the right and left sides correspond more closely 
in size and shape than might be supposed from an examination of the drawing. 
