50 



EDWARD MCCRADY, JR. 



As the animal pole at this time has absorbed all of the 

 overlying albumen, it probably begins to derive nutriment 

 from the so-called uterine milk a secretion from the uterine 

 glands to be described presently, which filters through the 

 shell membrane. The vegetal pole is still covered by albumen, 

 which it is absorbing slowly. 



Fig. 17 Uterine glands (Selenka, 1887). 



The uterine glands. Inasmuch as the uterine glands play 

 no part in the development of the vesicles until the sixth 

 day, I have postponed discussion of them until this point ; but 

 this arrangement necessitates a short digression now to sum- 

 marize their previous history. 



Selenka (1887) was the first to describe and figure the con- 

 dition of these glands during pregnancy (fig. 17). Hartman 

 ('23) traced their development throughout the oestrous cycle. 



