Memoir upon living and fossil Elephants. 263 



The membranous productions of the capsule oF the tooth 

 -retire towards the top and the sides in proportion as tlie cor- 

 tical which they deposit upon the enamel fills all the va- 

 cuum which remained between the diftercnt laminae of the 

 tooth. The peaks of these lamina are covered with cortical 

 like the rest, while ihey are not in use. One and the same 

 production of the capsule often deposits its cortical upon the 

 top of the lamina, which it again deposits upon the enamel, 

 onlv at the bottom. It happens also that the top of the in- 

 terval of the laminfE is already heaped up by the cortical 

 when the base is still separated : in this case, the bottom of 

 the capsular production is separated from the top, and does 

 not receive its nourishment any longer, except from its la- 

 teral adherences with the capsule. 



The deposition of the enamel begins almost with the trans- 

 udation of the osseous substance, and that of the cortical 

 follows closely after, in such a manner, that the summit of 

 each lamina is terminated in its three substances long before 

 its bottom, and that its adjoining laminse are soldered to- 

 ceiher by their sunmiits before being as yet hardened at their 

 bases. 



We mav add to all this, that these various operations are 

 not executed at the same time in all parts of the tooth, but 

 thev take place rather sooner before than behind. We may 

 easily imagine that the anterior laminas will be already united 

 among themselves by their summits and even by their bases, 

 when the interiiiediaic laminae will be still separated from each 

 other, at least by their l)ases; and when the posterior lanmias 

 are not even formed, and present only pointed and distinct 

 horns, which should form the summits of their notches. 



It therefore results from all we have advanced, that the 

 substances of which the leelh are composed are all formed 

 by excretion and by layers ; that the internal substance m 

 particular has nothingiin common with ordinary bones, ex- 

 cept in its chemical naaire, being equally formed ol gela- 

 tine and of calcareous phosphate ; but that it neither resem- 

 bles thtm in its texture, in its manner of forming itsclt, nor 

 in its growing, hs texture presents neither ccl.'ulosiiy nor 

 U 4 fibres. 



