Sir Everard Home on the 
238 
In the American opossum tfe hags are formed in 
the ovaria ; pass into the eceive the albumen, 
and are then impregnated ; the fetus in each uterus is aera- 
ted by one lateral tube. When expelled from the e uteri, 
the young are received into the marsupium, and became at- 
tached to the nipples of the mother. 
In the ornithorhynchi the yelk-bags are formed in the 
ovaria ; received into the oviducts, in which they acquire the 
albumen, and a^e impregnated afterwards ; the fetus is aera- 
ted by the vagina, and hatched in the oviduct, after which 
the young provides for itself, the mother not giving suck. 
In the pullet, the yelk-bags are formed in one ovarium, 
impregnated in one oviduct, and hatched out of the body. 
Explanation of the Plates. 
Plate XVI. 
Ovarium of the Kangaroo. 
Fig. 1. The ovarium of a young kangaroo laid open: 
natural size ; showing the corpus luteum. 
Fig. 2. The same section magnified four diameters, to 
show the corpus luteum more distinctly. 
Fig. 3. A section of the corresponding ovarium of the 
same kangaroo, magnified four diameters ; to show an inci- 
pient corpus luteum. 
Fig. 4. A similar section of the ovarium of an old kanga- 
roo : natural size ; in which there are two corpora lutea. 
Fig. 5. The same section, magnified four diameters, 
