') 
\ 
‘ \ 
\ 
! 
255—74 SIWALIK AND NAKBADA PEOBOSCIDIA. 
tooth of M. sivalensis, on the other hand, is implanted in a complete mandible, 
which, though slightly broken at the symphysis, shows that such symphysis was short 
like that of the living Indian elephant, and in fact agrees exactly with the man- 
dible of M. sivalensis represented in figs. 1 and la of Plate XXXV of the “ Pauna 
Antiqua Sivalensis,” which carries a six-ridged tooth with alternately disposed 
columns. Prom this identity in form of the two mandibles, and from the similar 
general structure of the two teeth, I have referred the specimen figured here to 
Jf. sivalensis. 
If the latter tooth he compared with the tooth of M. pandionis, it will be found 
that there is a little difference in the disposal and wear of the outlying tubercles in 
the two, while the hinder ridges are relatively highest in M. pandionis. The most 
important mark of distinction, however, is that the wear of the tooth of Jf. pandionis 
is almost in one plane, whereas the tooth of Jf. sivalensis is deeply concave in the 
middle. 
The figured tooth of Jf. sivalensis differs from the specimen figured in Plate 
XXXVII, fig. 8, of the Pauna Antiqua Sivalensis,” in having one ridge less, less 
alternately disposed columns, and more accessory tubercles. 
Relationship to Mastodon arvernensis.—'WQ have already seen that Sir Proby 
Cautley thought that the molars of Jf. sivalensis could not be distinguished speci- “ 
fically from those of Jf. arvernensis of the English Crag, ^ and the subsequent re- 
searches of Palconer confirmed this close relationship. Both species agree in the 
alternate arrangement of the mammillse of the ridges, but the mammillse of the 
European molars are generally less alternate than those of the Indian. The Euro- 
pean species does not seem to have any tendency to a pentalophodont type, and is 
further distinguished by having premolars, ^ which seem to be absent in the Indian 
species. Both species seem to have had a short elephantine mandible, without 
tusks. ^ 
The cranium of Jf. arvernensis is, I believe, unknown, and cannot therefore be 
compared with the very peculiar cranium of Jf. sivalensis. 
There can be no question but that the two forms are very closely allied. The 
differences indicated above afford, however, amply sufficient grounds for the speci- 
fic distinctness of the two forms. 
Relationship to M. pandionis. — Mastodon sivalensis may be regarded as present- 
ing the same kind of relationship to the trilophodont Jf. pandionis, as we have already 
shown to exist between the tetralophont Jf. perimensis and the trilophodont M. fal- 
coneri. In both the two first-named species the pattern of the crown of the molars 
is complex, with alternate columns, accessory outlying tubercles, blocked valleys, and 
irregularly shaped discs of dentine. The early molars of the two species are very 
different. 
' Included at that time under the name of M. angustidens. 
2 Pal. Mem., Vol. II, p. 34, 
3 Ibid., p. 44. 
