REPRODUCTION 



359 



Figure 200. Longitudinal 

 section of Humpback ovary 

 with corpus luteum {top). 

 The fluid in the follicles has 

 coagulated. Left: a corpus 

 albicans. {Photograph : Dr 

 R. G. Chittleborough, Ned- 

 lands, Australia.) 



lose a little of their moisture and become less taut. Others may suffer 

 degeneration (atresia) so that the ova in them never arrive at the possibility 

 of fertilization. Occasionally the ovaries, especially of old cows, display 

 particularly large follicles, but these must be considered pathological 

 phenomena. 



Our description of the Cetacean ovary applies exclusively to animals 

 that are not pregnant. In pregnant Rorquals, for instance, one of the 

 ovaries bears a spherical mass with the dimensions of a small football 

 (Figs. 199 and 200), the so-called corpus luteum (yellow body). (Actually, 

 the corpus luteum of Rorquals is pink, unlike that of Odontocetes and 

 most other mammals which is yellow). In Blue Whales the corpus luteum 

 has a diameter of 8 inches, and an average weight of 5I lb. (minimum 

 1 1 lb.; maximum i6ilb.). In Fin Whales, its average diameter is 

 4i inches, and its average weight is 2 lb. ( 14I oz.-6 lb.) . The corresponding 

 weights in Humpback Whales are if lb. (19 0Z.-4-J lb.) ; in Sperm Whales 

 if lb. (17J0Z.-2 lb. 10 oz.). In smaller Odontocetes and in many other 



