The structure and distribution of nasal glands in four marsupial species
JEAN E. KRATZING
Department of Veterinary Anatomy, University of Queensland, St Lucia, Queensland 4067, Australia
The glands which secrete into the nasal cavity in mammals fulfil a number of functions, including humidifying the incoming air, providing an appropriate environment for the olfactory receptor cells, and supplying a moving surface film to trap and remove foreign particles. In addition, they may also play a significant immunological role, since immunoglobulin A forms part of the protein secreted by the lateral nasal gland in the dog (Adams, Deyoung & Griffith, 1981).
The structure and distribution of nasal glands has been studied in the rat and a number of other mammals (Bojsen-M0ller, 1964), in the mouse (Cushieri & Bannister, 1974) and hamster (Adams, 1982), revealing an underlying similarity which permits gland classification into broad regional groups. However, there is considerable species variation, presumably since differing life styles place different priorities on the functions served by the glands.
Little has been published on the distribution of nasal glands in marsupials. The present study reports their presence, distribution and structure in four species of different body size, habitat and food selection. Tarsipes rostratus, the honey possum, is a blossom and nectar feeder of very small size, average adult male weight about 9 g (Strahan, 1983). The northern brown bandicoot, Isoodon macrourus, is a mixed feeder, average male weight about 2.1 kg. The koala, Phascolarctos cinereus, average weight about 11.9 kg, is mainly arboreal and feeds on a limited range of eucalypt leaves, and the largest species studied, the agile wallaby, Macropus agilis, is a herbivore inhabiting open forest and grassland (average male weight, 19 kg).