430 JAS. P. HILL. 



of a female immediately prior to the commencement of the 

 first parturition. But whatever may be the precise mode of 

 formation of the passage, this most remarkable method of 

 getting rid of the young would seem to be without parallel in 

 the whole mammalian class. 



New-born You'ng. — Here^ I need only point out that, so 

 far as my observations (cf. appendix) go, the new-born Pera- 

 meles does not appear to differ to any very great extent, in its 

 degree of development, from the new-born young of undoubted 

 non-placental Marsupials, e. g. Didelphys. 



Stage F. — P. obesula (post-partum). 



The material for this stage consisted of the genital organs 

 (less the cloaca) of a female with two pouch-young measuring 

 from crown to rump 23 mm. The left uterus, the larger of 

 the two, measured 15 mm. in length by 6 mm. in breath. 



Microscopical examination shows that the uterus has now 

 almost completely regained the resting condition. 



The mucosa, however, is just about half as thick as that of 

 the resting uterus. The epithelium of the uterine glands has 

 been laid down anew, and now consists of a low cubical epithe- 

 lium with fairly large ovalish nuclei. The gland lumen is 

 nearly always occupied by a finely granular coagulum, which 

 may contain cellular constituents. The interglandular con- 

 nective tissue is in parts fairly open in appearance, consisting 

 of a network of anastomosing cells ; in other parts it is quite 

 dense and compact owing to the presence of great numbers of 

 young connective-tissue cells. 



The syncytium and allantois have completely disappeared, 

 and the uterine epithelium now forms a continuous layer all 

 over the surface of the mucosa. It consists of a low layer of 

 cubical cells with rounded closely packed nuclei in a single 

 row. 



Over the greater portion of its extent the uterine surface is 



^ I hope later to return to this question, and also to consider therewith the 

 question of the " critical period " in Perameies (J. Beard, ' On Certain 

 Problems of Vertebrate Embryology,' Jena, 1896). 



