10 



FRANK E. BEDDARD 



the first of the series of the upper jaw, which will now be 

 described. It mil be noted, therefore, that here, as in the 

 upper jaw, the tooth series develops from behind forwards. 



Teeth of the Upper Jaw. 



In the case of the upper jaw I was also able to trace the 

 dental lamina to the very end, close to the condyle. It begins 

 here as a much shorter fold than it becomes farther forward. 

 The fold at the very first is more or less oval in transverse 

 section, and later appears club-shaped. It becomes separated 

 in fact into the oval free extremity and a much more slender 

 stalk. The expanded free edge of the dental lamina may be 

 traced forwards into the series of rudimentary teeth. The only 

 change at first in this region of the dental lamina is the increase 

 in size, at intervals and for the distance of a few sections, of 

 the expanded free extremity. Nevertheless, it is particularly 

 to be noted that where there are no signs of tooth formation 

 the ending of the lamina is still swollen. It has been asserted 

 and denied ^ that a swollen extremity of the dental lamina 

 argues the actual presence of a rudimentary tooth germ. It 

 would seem likely in the present case that the region of the jaw 

 which we are now considering will ultimately be furnished with 

 teeth. But I have no positive facts to fix the validity of this 

 decision. And, moreover, in view of the apparent agreement 

 in age of all the undoubted tooth germs in both jaws, it might 

 be argued with equal force that the terminal region is not to 

 be invaded by teeth. In this event the swelling of the edge 

 of the dental lamina will be an argument in support of those 

 who see in a terminal swelling no actual prophecy of teeth 

 in the same situation, however rudimentary those teeth may be. 



The accompanying figure (Text-fig. 6) shows an early tooth 

 follicle with the dental lamina therein and that it ends in a slight 

 swelling. It will be noticed that the terminal swelling is con- 

 tinued in the same straight line as the rest of the dental lamina. 

 The next figure (Text-fig. 7) shows a section some way farther 

 on towards the symphysis of the jaws ; and in this a slight 

 ^ See, for a brief summary of these views, Tomes (6, j). 357). 



