300 PROFESSOR OWEN ON SOME SPECIES OF THE EXTINCT GENUS NESODON. 
Of the genus offering the above osteological and dental characters, I have already 
r:r. 
„ 0,. Ot th. I...r i.w ~ >•" 
soecies of the size of the Zebra, called Nesodon Suhvam in honoui of its 
is^ indicated by detached molar teeth of the lower jaw. The species to which the 
Dortions of skdl above described belonged, seems, from the size of the first an 
second true molar tooth, to have been about the size of the Ftcugna, or of a large 
sheep and I propose to call it Nesodon ovinus. A fourth species, as aige 
Rhinoceros, is indLated by an upper molar tooth ; and I propose to call it Ae.odon 
” That'the specimens on which the species Nesodon minus is founded, did not belong 
to a young individual of the Nesodon imhricatus, is shown by the " 
extent occupied by the first four (deciduous?) grinders m the lower jaw. Plat . . 
figs 6 7 8 d .-1 1 and in that occupied by the first four grinders (preinolars) in the 
lower jlw of the Nesodon imbricatus, Plate XVII. fig. 11, P-; and by the ^-eat 
diffe" fcrin the size of the teeth, which, on the hypothesis of the wo alleged 
species being one, must hold the relation of temporary and successional teet i. , 
Srig af is most probable, that the first four grinders in the lower jaw o the 
Nesodontinus are milk-teeth ; yet these are displaced -ccee ed ™n.cahy y 
the preinolars, which are in most Herbivores smaller and less complex, and 
no Mammals larger and more complex, than the teeth they so displace ; such p e- 
molars never occupying a greater longitudinal extent, although they somenn es, 
when fewer in number than the deciduous grinders, occupy a less exten , m ja ^ 
of the adult animal. We may therefore safely infer that the four teeth occupy, g 
the extent of 3 inches in the lower jaw of the Nesodon tmhncatus, p fi». 1 1, 
not have risen into the place of the four molars, which only occupy the space 
1 Inrh q lines in that of the Nesodon ovinus, d 1-4, fig. 6. 
Tf nLt we compare the crown of the first true molar in the upper jaw of the 
Nesodon ovinus (fig.3,m.) with either of those (fig. 10) 
Memoirf to the Nesodon imhricatus, we shall obtain equally conchis 
that they have not belonged to the same species. 
Upper Molar Teeth o/ Nesodon imhricatus. 
The antero-posterior extent of the crown of »i . in the 
theNesodon imhricatus it is 15 lines; the greatest transverse 7'“^' ^ ‘ ' f j,,;, 
is 5 lines ; in N. imhricatus it is 9 lines. The generic conformity of the shape ot ti c 
•own and the disposition of the enamel is very close. Both the upper n ola 
(Plate XVII fig. 10 ^-eferred to the AWo» imhricatus have ^<=^>1 nnicl, worn, t^ 
Interio^ne, orcouise, the most. In this tooth the posterior division of the forked 
. . 1 cMr rr t LOC. Clt. p. 67. 
* Reports of the British Association, 1846, p. 06. 
