xiv. INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
elusion that H. antilopinus was probably monodactylate ; and also that the remains 
from the Punjab described and figured in the second volume of this work under that 
specific heading not improbably belong to a distinct species. 
Rliinoceros and Aceratherium. — The writer has come to the conclusion that 
there is no logical reason for generically separating from IViinoceros [vide 
“ Cat. Foss. Mamin. Brit. Mus.” pt. HI.^), since the American forms ranged by Cope 
under the names ApJielops, Ccenojms^ and Peraceras {vide supra Ami. II. p. ix.) indicate 
a complete transition between the two. 
Mastodon cautleyi, n. sp. Lyd. — The difficulty of referring detached teeth of 
the genus Mastodon to their proper species in cases where several allied forms occur 
in the same formation is so great, that errors in such determinations are almost 
inevitable unless a very extensive series of perfect specimens is forthcoming. In 
recently describing a molar of Mastodon latidens from Borneo, the present writer^ 
referred to certain SiAvalik specimens in the British and Indian Museums which 
appeared to indicate a more or less complete transition between typical molars of 
that species on the one hand and those of M. perimensis on the other. A subsequent 
examination of the specimens in question has however led to the conclusion that 
they cannot apparently be satisfactorily referred to either one of those species \ and 
as there can be no question as to the strongly marked distinction between typical 
molars of those two species, it has been thought, after considerable hesitation, 
advisable to provisionally apply a distinct specific name to the aberrant form, 
which may be called M. eautlcyi. The alternative would be to consider this form as 
a variety of one of the previously named species, but the difficulty then arises of 
saying with which it should be associated, since its upper molars present resemblances 
not only to those of the Siwalik M. latidens and M. perimensis^ but also to those of 
the European M. longirostris. 
The specimens on which this provisional species is founded are five in number, 
and are all cheek-teeth of the upper jaw; four of them being in an unworn con- 
dition. Three of these teeth, which are all from Perim Island, are in the British 
Museum, and are figured in the “Fauna Antiqua Sivalensis,” under the name of M. 
latidens: the first (pi. XL. figs. 2, 2a) is the right mm. 4 ; the second (pi. XL. figs. 3, 
3a) is the left m. 1, and is refigured of the natural size in woodcut fig. 5 ; while the 
third (pi. XXXI. figs. 6, 6a) is the left m. 3, and is refigured on a larger scale in Avood- 
cut fig. 6. The other tAvo specimens’ are in the Indian Museum, and are figured in the 
present Avork under the name of M. perimensis ; the firsF (vol. I. pi. XL.) being the 
partially- worn left m. 1, with the associated pm. 4, the formeP of which apparently 
agrees precisely with the homologous British Museum specimen, and the other® 
(vol. III. pi. XVI. fig. 2) the imperfect right m.2, in an unworn condition. All these 
1 In preparation. 2 ‘ Proc. Zool. Soc.’ 1885, pi. XLVIII. 
3 “ Cat. Siwalik Vert. Ind. Mus.” pt. 1. p. 97. No. A. 48. (1885). 3£. perimensis. 
. 4 AVTien describing this specimen in Calcutta the writer could not identify it with the one figured in the “ F.A.S.” pi. 
XL. fig. 3, owing to the small size of the figures in that work, which renders them almost useless for comparison. 
5 “ Cat. Siwalik Vert. Ind. Mus.” pt. I. p. 97. No A. 437. (1885). 31. perimensis. 
