716 
and rooting. Hence the author infers that the Tetracaulodon lived 
principally on roots, whereas the Mastodon, he says, consumed the 
large upper herbage. The superior tusks of this specimen measure 
only 19 inches in length, one-third having been “concealed in the 
skull,” and their greatest circumference is 9Linches. They possess 
the peculiarity of being larger at the apex than the base, the 
former also exhibiting indisputable marks of having been much 
used during the life of the animal. They were slightly curved up- 
wards. The enamel on the root is very thin, but it increases rapidly 
towards the extremity, where it is extremely thick. “ The bulb for 
the dental nerve” is stated to be small and to terminate suddenly in 
a point. 
With reference to the tusks of the lower jaw, Mr. Koch agrees 
to the view that the young animal possessed two, and the adult 
only one, situated on the right side. It was, he says, slightly 
curved downwards and then upwards, and in both old and young 
animals possessed the peculiarity of being equal in circumference 
at both extremities. The bulb for the nerve which nourished the 
tusk resembles minutely that of the upper tusks, both in adult and 
immature animals; and Mr. Koch is of opinion that this peculiarity 
of the lower tusks gives rise to “a suspicion of not merely a dif- 
ferent variety of the Tetracaulodon, but even of a new genus.” 
3. Tetracaulodon Tapiroides.—This specific distinction Mr. Koch 
has founded on the first grinder resembling that of the Tapir. He 
possesses the greater part of a skull and its two tusks, which were 
in their proper position when he found the specimen. The tusks 
are described as perfectly straight, but bent downwards like those 
of the Morse, to which, the author says, they bear a strong resem- 
blance ; and, from their worn condition, he believes that the animal 
lived on the roots of water-plants, &c. They are covered with a 
thick coat of enamel, and were concealed for one third of their 
length in the sockets; they are also stated to be large in proportion 
to the size of the skull; and the bulb is said to resemble that of the 
foregoing variety. 
Mr, Koch then calls attention to some vertebre in his collection 
belonging to a gigantic animal, but to neither the Mastodon nor 
the Elephant. ‘They consist, he says, of an extremely well- pre- 
served lumbar, and a second cervical vertebra. ‘The most striking 
character of these bones is stated to be the great size of the foramen 
in reference to the smallness of the body, the former being double 
the dimensions of that of the Mastodon. The author also says that 
the cervical vertebra presents two peculiar “ cavities, situated on 
the right and left of the root of the toothlike process,” and which he 
‘‘ considers to have been for the reception of two unusual muscles, 
to enable the animal to perform a peculiar motion with the head.” 
As he found these vertebra in the same deposit from which he ob- 
tained the skull and jaw, and as he conceives that the Tetracaulo- 
don must have possessed the power of moving head and neck in a 
peculiar manner whilst grubbing for its food, Mr. Koch believes that 
these vertebree belonged to that animal. 
