anatomical Structure of the Wombat. 307 
and the fibula, and another between the fibula and the 
tarsus. 
“ The fibula has a slight degree of motion on the tibia at 
its upper end, and a half rotatory motion on it at its lower 
end. Between the two bones is a strong muscle, which passes 
from one to the other throughout their whole length. The 
fibres have their origin from the inner edge of the fibula, and 
pass obliquely inward and downward to be inserted into the 
opposite surface of the tibia. When this muscle contracts, it 
pulls the fibula forwards, and produces a degree of rotation 
on the tibia, which turns the toes inwards. The anterior sur- 
face of the muscle is covered by a thin fascia or interosseous 
ligament, and there is another fascia less complete on its pos- 
terior surface. The muscle of the leg, corresponding to the 
biceps flexor of the human subject, is inserted into the poste- 
rior part of the fibula, and is an antagonist to the muscle just 
described. Its action brings the toes back to a straight line, 
but does not turn them outwards. 
This mechanism is met with in two animals, whose mode 
of life is very difl'erent, the one living on trees, the other not ; 
but as they both burrow in the ground during the night, its 
use appears to be for throwing back the earth while the 
animal is burrowing. There is nothing at all similar to it in 
the hind legs of the mole, or other burrowing animals. 
The internal structure of the stomach of the wombat re- 
sembles very closely that of the beaver, and is shewn in the 
annexed drawing. This is so difl'erent from that of the kan- 
guroo, and all the other animals of the opossum tribe, that it 
forms a very extraordinary peculiarity. 
The male organs of generation have been described by 
R r 2 
