They seem to connect together the Ungulata, Rodentia, and Carnivora.
We give a name to the class thus formed—carnivora, rodentia, etc.
The field mouse and rabbits are rodentia, the deer ungulata, the kangaroos marsupialia.
In the Rodentia there are generally thirteen pairs of ribs, which do not present any marked peculiarities.
They are perfectly harmless, and live on small animals, chiefly the rodentia.
