Professor Daniel 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 1882, notes:

    "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: