PLATE XL 



(Photographs about J natural size.) 

 Fig. I. Ovaries of immature Blue whale, No. 48. 



Fig. 2. Ovaries of adult Fin whale, No. 11 1. Many old corpora lutea 

 are present and a large follicle is seen bulging from the lower left-hand 

 side of the left ovary. 



Fig. 3. Ovaries of pregnant Fin whale. No. 173. The huge swelling on 

 the left-hand ovary is the corpus luteum of pregnancy. Both ovaries 

 have many old corpora lutea. 



Fig. 4. Ovaries of pregnant Fin whale, No. 175. The functional corpus 

 luteum here has a very pronounced neck. 



