530 
MR. OWEN ON THE MAMMARY GLANDS 
a tough capsule filled with a soft substance of a dark brown colour. The 
remaining ova varied in diameter from a line to the fiftieth part of an inch, 
giving an irregular tuberculate surface to the ovary, and a superficial resem¬ 
blance to the ovary or clutch in the bird: but in the Ornithorhynchus the ova 
are enveloped in a tough fibrous membrane, in which the traces of vascularity 
(at least after having been preserved in spirits,) are not perceptible, whilst in 
the fowl the ova are attached by narrow pedicles, and are covered by a thin 
and highly vascular membrane. The right ovary in this specimen was of an 
elongated form, attached to, and apparently developed from the ligament above 
mentioned ; it was a thin substance about half an inch in length, and nearly 
two lines in breadth, with the surface studded over with incipient ova. This 
appearance renders probable the supposition of Sir Everard Home that it may 
come into action at some period of the animal’s existence; but the traces of 
it in all the other specimens could only be recognised in a slight thickening 
of the ligament. The mammary glands in this specimen were each two inches 
four lines in length, eight lines in breadth, and nearly a line in thickness. 
The lobules of the gland had increased more in length than breadth, being 
almost as narrow as in the smallest gland. In both instances they were of 
the same colour and texture as in the largest glands. 
In the specimens in which the mammary glands had arrived at their full 
size, the ovary presented the following appearance. It was nearly as large, as 
respects length and breadth, as in the preceding case, but was much thinner, 
and its surface was rendered irregular by furrows and wrinkles. There were 
also minute granules of a black colour immediately beneath the outer covering, 
but the body of the ovary was composed of a loose cellular texture only. It 
may reasonably be concluded, therefore, on a comparison of these appearances 
with those exhibited in the ovaries previously described, that they indicated 
the condition of the ovary shortly subsequent to the performance of its pecu¬ 
liar functions, and that at this period, the circulation having been diverted 
to the neighbouring mammary organs, had contributed to their excessive 
development. 
In the female wherein the ovary and the uteri were in apparently the lowest 
stage of adult development, and exhibited no traces of recent action, the 
mammary glands presented a volume indicative of a corresponding degree of 
inactivity. Where the ovary had made a considerable advance towards per- 
