SIWALIK AND NARBADA PROBOSCIDIA. 
19—200 
premolars.. We have tlierefore now proof that all the milk-molars of Mastodons may 
be replaced by premolars. 
I shall, I hope, be pardoned for pointing out what appears to me to be a want 
of precision in Professor Cope’s description of the above-mentioned teeth. In that 
description the learned author, speaks of all the three anterior teeth as “ premolars,” 
apparently not recognizing their belonging to totally different series, though he men- 
tions that the last “premolar,” according to Owen, belongs to the milk-series. This 
fusion under one serial name, of teeth belonging to two totally different series, is a 
retrograde step from Palconer’s clear definitions. It does not appear that Professor 
Cope recognized the importance of his specimen in further elucidating the dentition 
of the Mastodons. 
Although we have thus seen that the antepenultimate and penultimate milk- 
molars may be replaced by premolars it appears to me that certain pre-molars of 
M. angustidens classed by the late Professor Herman von Meyer as the antepenul- 
timate and penultimate, are really the penultimate and last. In a left maxilla of a 
young M. angustidens figured by that distinguished palseontologisP, there are seen 
three teeth, the two first of which are less worn than the third, and which are 
consequently premolars ; the third tooth carries three ridges, and, the species being 
trilophodont, might be either the last milk-molar or the first true molar. By 
von Meyer the three* ridged tooth is classed as the third milk-molar {dritter milch 
backenzahn), while the two premolars are respectively classed as first and second 
(erster und zweiter erzatzhackenzahn) . This first and second, as being in front 
of the third milk-molar, must be equal to penultimate and antepenultimate. In 
fig. 12 of Plate V of the same memoir, von Meyer figures a two- ridged premolar, 
which he calls the second or penultimate {zweiter ersatzhackenzahn) . Now, 
in a cast of a young lower jaw of M. angustidens in the Indian Museum, below 
a three-ridged tooth, there is seen in its alveolus a replacing premolar, which is 
similar to, though smaller than, von Meyer’s lower premolar ; the former, as replac- 
ing the last milk-molar must be the last or third (fourth of the typical series) pre- 
molar, from which I infer that von Meyer’s is the same.^ Again, in the upper jaw 
the two premolars are far larger and more complex than the antepenultimate and 
penultimate premolars of M. 'productus., and I therefore think it is pretty clear 
that the former teeth really are the two last of the premolar series. The third tooth 
in von Meyer’s specimen will consequently be, if I am right, the first true molar. 
I shall have to refer to this question again, as it has an important bearing on the 
determination of certain teeth figured in this memoir. I may also mention that in 
fig. 16 of Plate V of the same memoir von Meyer has figured a detached three- 
ridged lower molar of M. angustidens, as the second lower milk-molai {zweiter milch 
hackenzahn) ; this tooth, I think, is certainly the thii*d milk-molar. The second 
lower milk-molar, as seen in a specimen from Eppelsheim in the Indian Museum 
(preceding a three-ridged tooth, and with the pressure-mark of a preceding tooth 
anteriorly) is a two-ridged tooth; tlie third milk-molar, succeeding the s(;X?ond, in the 
' Palffiontographica Vol. XVII, PI. Ill, fig. 1. 
^ See “ Les Enchainements du Monde Animal,” fig. 242. 
