318 proceedij^gs oe the geological society. 



and lower jaws in question would be regarded as belonging to 

 distinct animals of diiferent ages. 



To revert to the numerical determinations, tbe antepenul- 

 timate or first true molar is that regarding which there is the 

 most uncertainty. According to Corse, it consists of about fifteen 

 ridges. Cuvier has not specially defined the number. De Blain- 

 ville attributes to the upper antepenultimate fifteen ridges ; the 

 lower he has not characterized. Owen describes the tooth, 

 in general terms, as having the crown composed of 15 or 16 

 plates (ridges), with a length of from 7 to 8 inches. The result of 

 my observation is, that although the first true molar, in the Indian 

 Elephant, is manifestly larger in all its dimensions than the last 

 milk-molar, it ordinarily repeats the number of ridges shown by the 

 latter. The following are illustrations in the Museum of King's 

 College : — Besides the two young crania already mentioned, there is a 

 third, of adolescent age, which contains the last milk-molar and the 

 fii'st true molar above and below. The third milk-molar in the 

 upper jaw is nearly worn out ; behind it the antepenultimate true 

 molar presents a crown composed of twelve principal ridges, with a 

 front and back talon. The six anterior ridges are worn, the rest 

 being intact. The dimensions are — length of crown 6-3 inches, 

 width in front 2-1 inches, width behind 1-5. In the lower jaw of the 

 same specimen the last miUc-molar is worn out ; the antepenultimate 

 true molar presents a crown composed also of twelve principal ridges, 

 with front and back talons. The ten anterior ridges are worn : 

 the disks of wear are well crimped, and without any mesial expan- 

 sion. The dimensions are— length of crown 6-8 inches, width in 

 front 2 inches ; width behind 1-5. The cranium is well marked, 

 for reference, by the loss of the right tusk, the pulp-nucleus of which 

 had been destroyed, the third alveolus being nearly filled up. It 

 bears a record of having been presented by Mr. Hammond. 



In the collection of the Eoyal College of Surgeons there is a young 

 cranium, nearly of a corresponding age, in which the same teeth are 

 present. In the upper jaw, the last milk-molar is worn down to a 

 stump, having the indistinct remains of about five ridges. 



The antepenultimate true molar is in the middle stage of wear* 

 The crown presents twelve principal ridges, with fi'ont and back talons, 

 making in all fourteen divisions. The five anterior ridges and talon are 

 worn, the rest being intact. The dimensions are — length of croAvn 

 6-8 inches, width of ditto in front 2-4 inches. 



In the lower jaw of the same cranium, the last milk-molar is 

 nearly worn out ; the antepenultimate true molar has a crown com- 

 posed of twelve principal ridges, wdth front and back talons, the 

 latter of which has a small splent, appended to it. The ridges may 

 therefore be reckoned either as 12 or 13, according to the different 

 views of observers in regard to what ought to be considered 

 talons. The eight anterior ridges of the crown are in full wear. 

 The length of the crown is 7-8 inches*. 



I have now before me two very instructive detached specimens, 



* The other dimensions wonld have been inserted, but I have been unable to 

 identify this specimen in the Museum of the College.^ED, 



