30 
oyster, now extinct, from North Carolina. They are much larg- 
er than the modern forms. There are also numerous specimens 
from the Quaternary clays of Europe. 
HALL 61 . 
FIRST WALL CASE, RIGHT. — Fossil mammals of the Mi- 
ocene beds of the Sewalik Hills, India, and of strata in Au- 
stralia and Argentina of similar age, are here represented by 
numerous casts. These include casts of skull and limb bones 
of Diprotodon, a huge, ancient kangaroo; casts of skulls of 
Toxodon, Sivatherium and Nototherium; and of limb bones of 
Sivatherium. 
Toxodon was a quadruped of huge size, which combined 
characters of rodents, elephants and whales. Its teeth show it 
to have been an herbivorous animal and its habits were probably 
like those of the Manatee or sea dow. 
N ototherium was an Australian mammal, of the wombat 
type, though as large as the rhinoceros. It probably had some 
of the characters of the elephant, and was closely allied to the 
Diprotodon. The humerus indicates that it was a burrowing 
animal, but it is hard to understand how an animal of so great 
size could have been of such habit. 
Sivatherium was a four-horned antelope or giraffe of ele- 
phantine size. 
FIRST WALL CASE, LEFT. — Remains of the Mammoth 
and Mastodon, two great elephants which inhabited North Amer- 
ica during the glacial period and later. The remains include 
teeth, tusks and other bones, and a piece of skin, bearing hair, 
from the Mammoth found encased in ice in Siberia. Compari- 
son of the teeth will show how the Mammoth is distinguished 
from the Mastodon. The surface of the tooth of the Mammoth 
is flat and crossed by a number of ridges, while that of the 
Mastodon is raised into large tubercles which are more or less 
worn away according to the age of the animal. The great range 
of these elephants is illustrated by the fact that teeth are shown 
from South Carolina, Texas, Nebraska, Idaho, and Alaska. 
Some excellent tusks from Alaska are shown, found under 
ground while mining gold in that country. 
