868 
latter there is never more than one wholly, or 
two partially in place and use on each side at 
any given time; for like the molars of the 
Mastodons, the series is continually in progress 
of formation and destruction, of shedding and 
replacement, and in the Elephants all the 
grinders succeed one another horizontally, from 
behind forwards, none being displaced and 
replaced by vertical successors or premolars. 
The total number of teeth developed in the 
Elephant Professor Owen believes to be 
2.2 6.6 
Incis. ——- Molars —— 
0.0 6.6 
the two large permanent tusks being preceded 
by two small deciduous ones, and the number 
of molar teeth which follow each other being 
at least six; but Mons. Corse was of opinion 
that this replacement of teeth is repeated at 
least eight times in the Indian Elephant, which 
would consequently have thirty-two teeth suc- 
cessively taking their respective places in the 
jaws. 
The deciduous tusk makes its appearance 
beyond the gum between the fifth and seventh 
month; it rarely exceeds two inches in length, 
and is about a third of an inch in diame- 
ter at its thickest part, where it protrudes 
from the socket; the fang is solidified, and 
contracts to its termination, which is commonly 
a little bent and is considerably absorbed by 
the time the tooth is shed, which takes place 
between the first and second year. 
The socket of the permanent tusk in a new- 
born Elephant is a round cell about three lines 
in diameter, situated on the inner and posterior 
side of the aperture of the temporary socket. 
The permanent tusks cut the gum when about 
an inch in length, a month or two usually after 
the milk teeth are shed. The widely-open 
base of the tusk is fixed upon a conical pulp, 
which, with the capsule surrounding the base, 
progressively increases in size, stimulates a 
concomitant increase in the capacity and depth 
of the socket, which. cavity soon obliterates 
that of the deciduous tusk. 
These incisive teeth of the Elephant not 
only a other teeth in size, as belonging 
to a quadruped so enormous, but they are the 
largest of all teeth in proportion to the size of 
the body, representing in a natural state those 
monstrous incisors of Rodents which are the 
result of accidental suppression of the wearing 
force of the opposite teeth. 
The molar teeth of the Elephant are remark- 
able for their great size, even in relation to the 
bulk of the animal, and for the extreme com, 
plexity of their structure. The crown, of which 
a great proportion is buried in the socket, and 
very little more than the grinding surface ap- 
pears above the gum, is deeply divided into a 
number of transverse perpendicular plates, 
consisting each of a y of dentine, coated 
by a layer of enamel, and this by a less dense 
bone-like substance which fills the interspaces 
of the enamelled plates, and here more espe- 
cially merits the name of cement, since it binds 
together the several divisions of the tooth 
before they are fully formed and united by the 
28, 
.PACHYDERMATA. 
confluence of their bases into a common body 
of dentine. 
The manner in which these complex teeth 
are formed is a subject of great interest, and 
has been ably investigated by many celebrated 
anatomists, particularly by the two Ca 
father and son, M. Corse, Robert Blake, 
John Hunter, whose splendid preparations illus- 
trative of the process are contained in the 
Museum of the Royal College of Surgeons in 
London. It is to Cuvier, however, we are 
indebted for the most complete and lumi- 
nous exposition of this important piece of 
physiology, as may be gathered from the fol- 
owing account extracted from his great work, 
“ Recherches sur les Ossemens Fossiles. 
“ The molar tooth of the Elephant, like every 
other mammiferous tooth, is formed in the in- 
terior of a membranous sac, now general 
called the capsule of the tooth. This 
has in the Elephant a rhomboidal form, and is 
closed on all sides, excepting the small open- — 
ings for the passage of nerves and vessels. It 
is lodged in a bony cavity of the same be ‘ 
as itself, excavated in the maxillary bone, 
afterwards forms the socket of the tooth.” 
“ It is, however, only the external lamina of 
the capsule which is thus simple in its mpm 
ment, the inner lamina being, as in all « | 
herbivorous animals, thrown into numerous 
folds, as will be understood when we have 
described the pulp upon which the tooth is 
formed.” ; : 
“ This pulp has in every animal its liar 
arranger To represent that of the I Ele- 
phant, we must imagine that from the bottom 
of the capsule as from a base, there arise nu- 
merous parallel and transverse walls whi 
mount upwards towards that part of the 
sule which is placed next to the gums. These 
little walls are only adherent to the floor of thi 
capsule, their opposite extremity or summ 
being free from all adherence.” 
“ The free summit is much thinner than th 
base, so that it might be called the edge, ar 
is moreover deeply cleft in many parts, so ast 
form numerous sharp points and indentatio 
The substance of these little walls is soft, trai 
parent, and very vascular, containing ap 
rently much gelatine: it becomes hard, 
and opaque in spirits of wine.” 2 
“It will be now easy to understand 
manner in which the inner membrane of 
capsule is folded, if we imagine it to form ] 
longations which penetrate into all the inte! 
between the little walls above described. T 
prolongations adhere to the u 
capsule, that is, to the side of Pip Pnich is T 
the gums, and also to its lateral pari 
are not adherent to its base, from 
little gelatinous walls above described 
Consequently it is easy to understand t 
may be a continuous cavity amazin 
upon itself, extending between all t 
nous walls (which are descending in the u 
teeth, ascending in the lower teeth) and tl 
membranous partitions (ascending in the uj 
teeth, descending in the lower teeth.” 
“It is in this conceivable cavity that the 
