SIWALIK AND NADBADA PEOBOSCIDIA. 67—248 
skull) is so utterly unlike tlie first true molar of M. perimensis (Plate XL), that 
this alone would he sufB.oient grounds of distinction. 
An analogous instance of two species of Mastodon, the one with a trilopho- 
dont and the other with a tetralophodont formula, is afi^orded by the European 
M. angustidens and M. longirostris, in both of which the true molars are formed 
on the same general plan, and present trefoil islets of dentine on their worn 
columns.^ 
Distribution. — Remains of this species have been obtained from the Siwaliks 
of the Punjab to the west of the Jhelum and in Perim Island. I am not quite 
sure whether this species occurs in Sind, as I have some fragmentary molars from 
that district which may belong to M. perimemis. As no specimens of the teeth of 
this species were obtained by Ealconer and Cautley in the more easterly Siwaliks 
or Burma, it is probable that this species did not extend its range much to the east 
of the Jhelum. 
Species 5 : Mastodon sivalensis, Ealconer & Cautley. Pis. XLI, fig. 2, XLIV. 
Ristory .---ThQ first notice of Mastodon sivalensis seems to have appeared in a 
paper read by the late Sir Proby (then Captain) Cautley before the Asiatic Society 
of Bengal in June 1836.^ In that paper it appeared that the author considered 
certain molars of a Mastodon a dents etroites from the Siwalik hills to belong to a 
variety of the Mastodon angustidens ® of Cuvier ; to this variety he gave the name of 
M. sivalensis. In a paper published in December of the same year in the “Journal 
of the Asiatic Society of Bengal by the same author, the same conclusion was 
arrived at as to the specific relations of this Siwalik Mastodon. 
It thus appears that the name Sivalensis was given by Sir Proby Cautley alone. 
In Dr. Ealconer’s subsequently published table of the species of Mastodon and 
Elephant,® Mastodon sivalensis appears as a distinct species, with the names of 
both Ealconer and Cautley affixed to it. In that table the species is placed among 
the tetralophodont Mastodons, with the description “ Colliculi numero 5, obtusi 
alternatim mammillee, valliculse interruptse,” wdth the remark “ the only known 
species indicating a Pentalophodon-type.” In the same memoir® (which was 
published in April 1857), Dr. Ealconer remarks : — “ Mastodon sivalensis is regarded 
as having five ridges to the intermediate molars, instead of four; but this re- 
markable character being restricted at present to a single species, it was deemed in- 
expedient to form a systematic section for it alone, and it is ranged at the end of the 
* Pal. Mem., Vol. II, PI. III. 
* Jour. As. Soc., Bengal; Vol. V, p. 294 ; Pal. Mem., Vol. I, p. 126. 
* M. angustidens included the tetralophodont M. anernensis, as well as the trilophodont form to which the 
me is now restricted. 
Pal. Mem., Vol. I, p. 127.— J. A. S. B. Vol. V, p. 768. 
* Ihid., Vol. II, pp. 14, 15. 
‘ Ibid., p. 18. 
