SKIN AND REPRODUCTIVE ORGANS OF NOTORTCTES. 335 



tlieir nuclei and become disintegrated, so that the ball 

 contains a greater or less quantity of broken-down material, 

 which is passed to the exterior by the duct and cloaca. 



In the region of the cloacal opening are numerous solitary 

 large hairs. Associated with the bundles of hairs are also 

 very greatly developed sebaceous glands, which may extend 

 below the hair-roots, but do not occur unless in connection 

 with the hairs. They are only found around the hinder end 

 of the cloaca, and always lie outside, and generally separated 

 from, the muscular wall of the cloaca. 



We have in Notoryctes, therefore, representatives of three 

 of the types of glands, described by Professor Disselhorst 

 and others as found in connection with the reproductive 

 organs in Marsupials, viz. in Cuscus orientalis, Smin- 

 thopsis crassicaudata, Macropus robustus, etc. [cf. 

 1, pp. 154 — 163], viz.: 



(1) The tubular glands lined by a single layer of cylin- 

 drical epithelial cells. 



(2) The rectal or anal gland with a duct unbranched, as in 

 Sminthopsis, and Cuscus, and Antechinomys, leading into the 

 cloaca. 



(3) Hair glands — large complicated sebaceous glands 

 which do not here, however, lose their close relationship to 

 the hair-follicles, as they do in Sminthopsis, etc., where 

 they come into connection with the tubular and the rectal 

 glands, and lie amongst the muscles of the cloacal wall 

 [1, p. 161, fig. 159]. Nor is there here any special develop- 

 ment of muscles around these enlarged sebaceous glands, as 

 described by V. Den Broek for Cuscus orientalis [1, 

 p. 161]. 



As to the morphology of the rectal or anal gland which 

 V. Den Broek has considered to be a highly developed 

 modified sebaceous gland [1, p. 163], this seems to me most 

 probable from the somewhat similar general internal arrange- 

 ment of some of the larger groups of sebaceous glands 

 found around the cloacal opening of Notoryctes — though 

 these have not in this form a striated muscular investment 



