Pancreases from three male and three female adult Spinifex hopping mice (Notomys alexis) were studied. No correlation was found between pancreas weight and body weight. Estimations of islet tissue mass and of individual cell types were made on paraffin sections of Bouin‐fixed tissue taken from head, neck, body and tail regions of pancreas of each animal. Islet tissue mass was assessed using a linear scanning technique on sections stained with haematoxylin and eosin, and was compared with body weight. Specific cell types were assessed using a point‐intercept method, on aldehyde‐fuchsin‐stained sections for beta (β) cells, and on immunoperoxidase labelled sections for alpha (α) cells (glucagon) and delta (δ) cells (somatostatin). Positive regional differences noted were a greater proportion of islet tissue in the tail region, and a lower proportion of α cells in the head region. Alpha cells were peripherally situated in the islets. These results show some elements of agreement with a previously proposed hypothesis regarding the general patterns of arrangement of the mammalian endocrine pancreas.

The pancreas of six possums, both male andi female were isolated. The relationship between the weight of the pancreas and the weight of the animal was then calculated. Sections were stained with haemotoxylin and eosin and islet tissue mass estimated using a linear scanning technique in each of the regions of the pancreas: head neck, body and tail. A uniform distribution was shown. The relationship between the average islet mass and body weight was calculated. Sections were stained with aldehyde fuchsin in each of the regions, head, neck, body and tail using a Wild‐M501 semiautomatic sampling microscope. Beta Grimelius' silver nitrate stain in each of the regions: head, neck, body and tail. The alpha cells were also estimated by using a Wild‐M501 sampling microscope and a uniform distribution was shown.

With 1 plate in the text) Pancreases from three male and three female echidnas (Tuchyglossus uculeutus), possums (Trichosurus vulpeculu), grey kangaroos (Mucropus fuliginosus), spinifex hopping mice (Notomys alexis) and water rats (Hydromys chrysoguster) were studied using a point-intercept method and Weibel graticule (Weibel, Kistler & Scherle, 1966) on sections stained by an immunoperoxidase method for pancreatic polypeptide (PP). PP cells were assessed in the head, neck, body and tail regions. There was a greater percentage proportion of PP cells in the head than in the other regions of echidna, possum and water rat. PP cells were not identified in grey kangaroo and spinifex hopping mouse, although control sections were positive.These results show some agreement with a previously proposed hypothesis (Bonner-Weir & Weir, 1979) concerning the distribution of cell types in the mammalian endocrine pancreas.

Six Grey kangaroos, both male and female, were shot and weighed. The pancreas was isolated, weighed and samples fixed in Bouin's solution. Using a linear scanning technique (Carpenter & Lazarow, 1962) the mean islet tissue mass was estimated in head, neck, body and tail regions. A uniform distribution was found in all regions. The relationship between pancreas weight and body weight and islet mass in relation to body weight were calculated. Sections stained with aldehyde‐fuchsin (Gomori, 1950), Mallory's phosphotungstic acid haemotoxylin and modified Davenport's technique (Epple, 1967) were prepared. Using a Wild‐M501 semiautomatic sampling microscope and a Weibel graticule (Weibel et al., 1966) the percentage volume of β cells, α cells and δ cells were estimated respectively in the head, neck, body and tail regions of the six samples. The α cells or glucagon‐producing cells were the most predominant as these macropodid marsupials are well adapted to dealing with hypoglycemic conditions. They were uniformly distributed in all regions.

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