Cunningham also observed that the thylacine gut was richly supplied with Peyer's patches, the largest of which commenced about 40.5 cm (16 in.) from the anal opening and proceeded along the gut some 57 cm (22½ in.) in the male specimen and 35.5 cm (14 in.) in the female specimen.  Peyer's patches are a collection of large oval lymph tissues that are located in the mucus-secreting lining of the small intestine. These lymph nodules are especially abundant in the ileum, the lowest portion of the small intestine. The Peyer's patches contain high concentrations of white blood cells (or lymphocytes) that help protect the body from infection and disease.
 

With reference to the spleen, Cunningham observes that it is an elongated tongue-like structure placed obliquely across the abdomen and that a small finger like extension protrudes from the right side of the body of the spleen and projects towards the kidney.  Cunningham notes that the pancreas is well developed and that the liver is divided into right and left segments with the left segment being smaller than the right and showing no sign of sub-division into lobes.  A central cleft divides the right segment of the liver into two equal sized lobes.  The kidneys present the usual reniform outline with a small and constricted sinus.  In section, the medullary substance was uniform with a thin cortex.  The bladder, which he observes was in a contracted state, was remarkable for its small size - not larger than a small walnut.  In shape it was ovoid with thick muscular walls.

. Fig. 3 - A portion of the lower part of the intestinal canal of the thylacine which has been inverted and distended with alcohol to display the large Peyer's patch.  Fig. 4 - Another prepared section of thylacine intestine which shows a small Peyer's patch.  From Marsupialia Plate X - Thylacine & Cuscus, from "The Voyage of H.M.S. Challenger" (1882).

    Cunningham concludes with his observations on the genitourinary system of the male and a description of the marsupium of the female specimen.  He was unable to make any comment on the female reproductive tract as the specimen in his possession had been damaged.  To this day, his work has not been equalled and forms the core of our knowledge on the thylacine's internal anatomy.

    The Zoological Society in London purchased a male and female thylacine from Dr. Bingham Crowther of Launceston in November 1884.  Both of the thylacines were classed as near adults.  They arrived at the London Zoo on 14 November 1884.  The male survived until 5 February 1890 and the female died on 2 April 1893, which at 8 years and 131 days is the record longevity for a captive thylacine.  Frank E. Beddard was prosector to the Zoological Society in London and a lecturer in Biology at Guys Hospital.
 

. A sleeping male thylacine at the Hobart Zoo (Beaumaris site), circa 1916.  The tail of another individual can be seen extending from the right.  Although some authors have stated that the testes of the thylacine are held within a kind of "pseudo-pouch" formed by folds of skin, this photo indicates that this is clearly not the case (at least, not at times when the animal is in a relaxed state).  Rather, the testes normally hang suspended below the level of said skin flap, as is so with the closely related Tasmanian devil.  While some non-technical references have mentioned that in the thylacine both sexes possess pouches, it is important to point out that the insunk, pocket-like area which surrounds the male's scrotum is in no way similar to the true marsupium of the female, which is of course used to carry the young.

Beddard dissected the male thylacine and went on to describe both the brain and scrotal pouch of the animal in the Proceedings of the Zoological Society (Beddard 1891).  He was surprised to find a rudimentary "pouch" present in the male but recalled that Sir Richard Owen had observed this feature many years previously.  The region around the scrotum is hairless and insunk to form a sort of cup-like "pouch" comprised of a skin flap which reaches across the front and sides, gradually disappearing posteriorly.  It may possibly assist in thermoregulation, although Pocock (1926) suggested that it may serve as a protective structure for the normally pendulous scrotum when the animal is moving at high speed (e.g. when chasing prey).  As is the case with all marsupials, the male's testes are positioned anterior to the penis, rather than vice versa, as in most placental mammals.