PART 1.] 
71 
hydeiker : Notices of Siwalik Mammals. 
Mastodon perimensis, Falc. 
This species of Indian Mastodon has hitherto only been known from the mam- 
maliferons bods of Perim Island in the Gulf of Cambay.' Among the specimens 
of Mastodon teeth in Mr. Theobald’s Siwalik collection from the Punjab there is 
one complete lower jaw, and several detached molars which must be referred to this 
sjjecies and which prove its range into that region. The molars of M. perimensis 
are at once distinguished from those of M. latideri'S by the transverse valleys being 
greatly blocked by tubercles, by the ridges being higher, and by there being a 
slight alternation in the arrangement of the inner and outer columns of the latter. 
The same teeth arc distinguished from those of M. sivalens'is by the number of 
ridges being less, and by the ridges being less alternately di825osed, and the 
valleys being in consequence more nearly transverse. Among Mr. Theobald’s 
specimens are a first and a second njiper true molar which are more complete than 
any specimens I'eprosented in the “ Fauna Antiqua Sivalensis of one of these 
specimens I shall hope to give a figure on a future occasion. 
Some fragmentary Mastodon molars from Sind collected by Mr. Blanford, 
belong, I think, to this species. 
The lower jaw belonged to a compiletely adult animal, and contains the two 
ultimate molars; the first of these teeth is imperfect; the second is, however, com¬ 
plete, and contains five transverse ridges and a talon, according to the normal 
tetralophodont formula. 
This jaw agrees with the lower jaws of other Mastodons and differs from those 
of elephants, in that the summit of the coronoid process extends ujJwards as high 
as the condyle; the coronoid and condyle are, however, more closely approximated 
than in other species of the genus. The inferior and posterior borders of the 
jaw are nearly at right angles to each other, the angle being rounded off. 
The symphysis of the mandible is pi-oduced into an elongated spoilt, extend¬ 
ing more than a foot in advance of the first molar; the symphysis is three 
inches longer than the last molar. This sjiecimen does not exhibit any traces of 
incisors; but another specimen of the symphysis of the same species, also col¬ 
lected by Mr. Theobald, shews a small cavity on the left side of the extremity, 
which is quite likely to be a semi-obliterated dental alveolus. It is therefore 
quite possible that this species with a spatulate mandible may have been fui-nishcd 
with incisors, which were shed before the animal became adult. If this be so, 
the species would agi’ee in character with the European Mastodon longirostris, 
which also has a spatulate mandible and lower incisors. 
The most important measurements of this specimen are as follows :— 
Lengtli from Linder border of last molar to distal extremity of Byrnphysis . 29'0 
„ „ anterior boixlcr of penultimate molar to „ „ . 13’5 
„ of last molar 10'7 
Interval between condyle and coronoid process .... 5 0 
Mastodon latidons. 
In this species, I have lately discovered that the last milk-molar of the upper 
jaw was disiffacod vertically by a simjilor prcmolar, which was not previously 
' Falconer’s Pala:ontological Memoirs, Vol. II, p. 15. 
