The external characters of pouch young of four Australian species of the family Peramelidae have been examined and their principal dimensions are recorded. Three of these bandicoots seem to be in danger of being added to the growing list of extinct marsupials.
Particular reference is made to the distribution of the sensory papillae and vibrissae. The numerical constancy of most groups of vibriwae is very marked. In tables 111 and IV, I have summarized the distribution of the vibrissae in seven of the Australian bandicoots.
Digits 2, 3 and 4 of the manus of newly-born young of Perarneles gunnii and Isoodon obesulus bear deciduous claws which are shed soon after the embryo reaches the pouch. The presence of deciduous claws in bandicoots is reported here for the first time. These remarkable claws suggest that the embryo makes its way to the pouch by its own unaided efforts.
On the pes, claws are not discernible on newly-born young.
In all but the smallest pouch young the sex may be determined by external examination.