MAMMARY GLANDS IN MONOTKEMATA. 



761 



596 





in minute globules through 

 the parenchyma, and at a 

 distance of an inch it en- 

 tered a central duct, down 

 which it freely ran to the 

 areola, where it escaped 

 externally from one of the 

 minute orifices just de- 

 scribed. This process was 

 repeated on most of the 

 lobes with similar results : 

 the greater part of them 

 terminated by a single duct 



597 



ad, Oriiitliorliyncluis; nat. size, i.xxxi'. 



Mammary areola, Ornithorliynchus ; nat. 

 size. lixxvi'. 



opening exteriorly and dis- 

 tinct from the rest, but in 

 a few instances the ducts 

 of two contiguous lobules 

 united into one, and in these 

 cases the mercury returned 

 by the anastomosing duct 

 and penetrated the sub- 

 stance of the other lobe as 

 freely as that into which 

 the pipe had been inserted. 

 Some of the lobes injected 

 by the reflux of the mercury 

 through the duct, and of 

 which it was more certain 

 that the glandular structure 



