72 Mr. Morean’s Description 
of the marsupial bones towards each other; and being situated 
immediately behind the mamme, they are altogether prevented 
by that circumstance from affording the slightest support to 
the mamma itself. 
The marsupial bones thus confined in their situation by liga- 
ments, and by the surrounding muscles in which they lie imbed- 
ded, afford from their situation a firm inferior support to the 
abdominal viscera, and form an unyielding partition between 
those parts and the pouch. But another important purpose 
seems to be answered by these structures. I have already de- 
scribed two muscles, which are formed for the purpose of com- 
pressing the mammary gland; and I have mentioned also the 
continuity of these two muscles by the interlacement of their 
fibres over the linea alba (tab. 5. f. a.). These muscles form 
from their situation a sort of girdle around the belly immediately 
above the pelvis, and would necessarily, when put into action, 
press the mammary glands against the comparatively yielding 
sheet of abdominal muscles which lies behind them, were it not 
for the marsupial bones, which prevent any compression of the 
lower part of the abdomen from the action of the mammary. 
muscle, and at the same time receive the glands themselves 
upon their concave anterior edges. These edges afford a hard 
and solid point of resistance, against which the glands are 
pressed ; and their secretions are thus forced through their ex- 
. cretory ducts towards the teats. 
It appears to me probable, that i in the Kangaroo, the loose 
connection of the mammary gland to the subjacent textures 
may allow of its being drawn backwards and forwards across the 
edge of the marsupial bone, by the alternate contraction and 
relaxation of its proper muscle, and thus the process of emptying 
its ducts by pressure may be considerably facilitated. 
That Nature in other cases avails herself of the agency of 
muscular 
