THE MAMMALIAN SEXUAL CYCLE 47 



(Hammond), as tliougli tlie clianges belonging to two short cycles 

 had at this point been telescoped. The brief period of " rest " 

 between the times of lieat in polyoestrous mammals was called 

 by Heape the ''dioestrum," and the short cycle the dioestrous cycle. 





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MM.- 





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Fig. 27. — Discharged follicle of rabbit nineteen hours after coition, or 

 about nine hours after ovulation. The epithelial cells are in process 

 of hypertrophy and there is some ingrowth of connective tissue from 

 the theca. The place of rupture is widely open. Haemorrhage is 

 slight. Outside the follicle are interstitial cells of large size. 

 (L. F. Messel.) 



but as just indicated, the changes which take place during the 

 " dioestrum " in the ovary, the uterus, and the mammary glands 

 seem to imply the occurrence of an abbreviated pseudo-pregnancy. 

 The secretion from the uterine glands at the oestrous periods 

 facilitates the progress of the spermatozoa at this time, and it 

 is to be noted that the contents of the cervix in cattle and horses 

 are more liquid at oestrus than at other stages in the cycle 



