TYPES OF (ESTROUS CYCLE 



53 



Mammary Cycle. The mammary cycle in the unmated rat 

 and also the development of the gland during pregnancy have 

 been dealt with by Myers (472; and Sutter (605). The former 

 states: ' If pregnancy does not occur with the iirst ovulation the 

 mammary glands undergo slight retrogressive changes; how^- 

 ever, as the next ovulation approaches the mammary gland 

 takes on a new development. Similar changes can be observed 

 with each succeeding ovulation until pregnancy occurs.' 



(/) RABBIT AND FERRET 



The rabbit and ferret correspond in two peculiarities; oestrus 

 persists throughout the breeding season in the absence of 



Fig. 26. — Uterus of Rabbit in CEstrus. 

 The stroma is glandular, but compact. 



