Marsupials are characterised by development in the pouch or marsupium,
and a prolonged reliance on lactation to raise their young.
J. Cunningham (1882), in his description of the marsupium of the
female thylacine brought back with the HMS Challenger expedition in 1876,
and published as part of the
Challenger report in
"It was evidently
a very young specimen. This was manifest not only by its small size
but also by the immature condition of its bones. I am inclined to
believe that it had never borne young. The marsupium was oval in
form and exceedingly shallow. Its long axis, which was directed from
before backwards, measured two inches, whilst its transverse diameter was
one and a half inches. In front and behind there was little or no
demarcation between the pouch and the surrounding skin of the abdomen.
Laterally, however, it was well mapped out by prominent overhanging folds
of integument. The skin forming these folds and the floor of the
marsupium was of a very delicate texture and slightly wrinkled. With
exception of some sparse white downy hair it was quite bare. At the
limits of the pouch this downy hair was suddenly replaced by the ordinary
hairy coat of the animal. On the floor of the pouch there were four
small conical elevations. These were very slightly raised above the
general surface, and were situated in the centre of the pouch. On
the summit of each elevation there was a minute aperture barely visible
to the naked eye, and on applying a magnifying glass and separating the
lips of the opening with a needle an exceeding minute teat was observed
within. The conical elevations, therefore, simply represented the
integuemental sheaths of the teats. In the description of the mammary
organs of a Kangaroo by Mr. Morgan (Trans. Linnean Soc., 1826), it is stated
that the teats: "after once being developed by protrusion from their original
situation in the substance of the gland, never again recede to their former
condition, but constitute permanent marsupial teats throughout the rest
of life". This statement confirms me in my opinion that the female
Thylacine was in a virgin condition".
Sir Richard Owen
(1868), the English biologist, comparative anatomist and palaeontologist
notes with reference to the dimensions of the pouch:
Scottish anatomist Prof. Daniel J. Cunningham (1850-1909).
marsupium (pouch) of the female thylacine, with aperture open to display
the four teats. Source: Pocock, R., 1926. The
external characters of Thylacinus, Sarcophilus and some related
Proc. Zool. Soc. Lond. 1926: 1037-84.