650 UNGULATES. 



Processes of the capsule descend from its summit into the 

 interspaces of the dentinal pulp-plates, and consequently resemble 

 them in form ; but they adhere not only by their base to the surface 

 of the capsule next the mouth, but also by their lateral margins to 

 the sides of the capsule, and thus resemble partition-walls, confining 

 each plate of the dentinal pulp to its proper chamber ; the margin 

 of the partition opposite its attached base is free in the interspace 

 of the origins of the dentinal pulp-plates. The enamel-pulp, which 

 Cuvier appears to have recognized under the name of the internal 

 layer of the capsule, is distinguishable by its light blue sub-trans- 

 parent colour and usual miscroscopic texture, adhering to the free 

 surface of the partitions formed by the true inner layer of the capsule. 

 Although the enamel-pulp be in close contact with the dentinal pulp 

 prior to the commencement of the formation of the tooth, one may 

 readily conceive a vacuity between them, which is continued unin- 

 terruptedly, in many foldings, between all the gelatinous plates 

 of the dentinal pulp, and the partitions formed by the combined 

 enamel-pulp and the folds of the capsule. According to the excre- 

 tion-hypothesis this delicate apparatus must have been subjected 

 to compression in the unyielding bony box by the deposition of 

 the dense matters of the tooth in the hypothetical vacuity be- 

 tween the enamel and dentinal pulps ; a process of absorption 

 must have been conceived to be set on foot immediately upon 

 such altered condition of the gelatinous secreting organs ; and the 

 secreting function must be supposed to have proceeded, without 

 any irregularity or interruption, while the process of absorption was 

 superinduced in the same part to relieve it from the effects of 

 pressure produced by its own secretion. 



The formation of the dentine commences immediately beneath 

 the membrana propria of the pulp : a part which Cuvier distinctly 

 recognised, and which he accurately traced as preserving its relative 

 situation between the dentine and enamel, throughout the whole 

 formation of the dentine, and discernible in the completed tooth * as 

 a very fiine greyish line, which separates the enamel from the internal 

 substance' or dentine. 



The calcitication and conversion of the cells of the dentinal pulp 



