316 PKOCEEDIlirGS OF THE GEOLOGICAL SOCIETT. 



twelve principal ridges, with a talon in front and behind. The first 

 ridge and anterior talon are alone worn, the two last ridges and talon 

 being unconsolidated and separate. This tooth measures in length 

 of crown 5-2 inches, by a width in front of 1-5 inch. 



In the lower jaw of the same specimen the pennltimate milk- 

 molar presents eight principal ridges in a length of crown of 2*6 

 inches. The last mUk-molar is partly imbedded in the alveolus, and 

 the posterior portion concealed. Of the eight emerged ridges, the 

 four anterior are worn. The diameter of the tusk (replaced) in this 

 cranium is l-l inch. 



A detached cranium, in the same museum, furnishes the corre- 

 sponding teeth in the lower jaw, but a little older, and with the crown 

 fully emerged from the alveolus. The penultimate presents eight 

 principal ridges, with a small talon-splent behind. The crown is 

 well worn, and measures — length 2*4 inches, width in front "9 inch, 

 width behind 1'2 inch. The last lower milk-molar has a crown 

 composed of twelve principal ridges, with a posterior talon ; the four 

 anterior ridges are worn, the rest being intact, and the whole united 

 by cement. The crown measures, in length, 4-5 inches, by a width 

 in front of 1-55 inch. The cranium in this case, although older, is 

 of a smaller variety than that previously described. 



There are several young crania in the Museum of the College of 

 Surgeons yielding the same teeth. In one very immature specimen 

 (A) the antepenultimate upper is composed of four ridges and a talon, 

 and the lower of four ridges. Of the penultimate upper and lower, 

 each presents only seven ridges, with front and hind talons. In 

 another (B) which is a little older, the penultimate, much worn, and 

 the last, partly in use, are shown above and below. The penultimate 

 upper exhibits the remains of eight ridges ; the lower is worn out. 

 The last upper milk-molar of the same specimen, and the last lower, 

 show twelve ridges each, with a front and back talon. 



Taking the data afforded by these examples and a great many 

 others which I have seen in different collections, the ridge-formida 

 of the milk-molars in the Indian Elephant, exclusive of talons, is 

 ordinarily thus : — 



4-h8 + 12 

 4 + 8-1-12* 

 In regard to the penultimate milk-molar, an exception is admitted 

 in the case of the young cranium (A), where this tooth, both above 

 and below, is stated to present seven ridges in addition to front and 

 hind talons ; biit the hind talons in these cases may be regarded as 

 last ridges. Cuvier adopted the numbers assigned by Corse, namely, 

 four ridges to the tooth here designated the antepenultimate, 8 or 9 

 to the penultimate, and 12 or 13 to the last milk-molar. But it is 

 to be remarked that Corse made no distinction between the talons 

 and the ridges proper. De Blainville, in the descriptive details of 

 these teeth, assigns to them in succession, respectively, 4, 8, and 11 

 ridges to the upper, and 4, 9, and 11-12 ridges to the lower. Owen 

 describes the first or antepenultimate as having 4 plates, the penul- 

 timate 8 or 9 plates, and the last from 11 to 13 plates. Taking 



