204 Mr. W. Heape. 



Stage VI. The uterine epithelium degenerates and ruptures, and 

 the blood contained in the lacunae is poured into the uterine 

 cavity. 



Stage VII. Denudation follows, and the formation of the mucosa 

 menstrualis takes place in the same way and to the same 

 extent as in S. entellus. 



Stage VIII. The recuperation takes place as in 8. entellus. With 

 regard to the new uterine epithelium I find fresh evidence in 

 support of my contention that it is formed, not solely from 

 epithelial elements which already exist, such as the torn 

 edges of glands, but also directly from elements of the stroma 

 tissue. 



Ovulation in Macacus rhesus. Only one case has been met with 

 in which it can possibly be supposed that ovulation and menstruation 

 have occurred simultaneously ; this is the only case in which a 

 recently discharged follicle was found in the ovary of a menstruating 

 Macacus rhesus ; it does not follow that ovulation in this case was 

 brought about by menstruation ; indeed, the absence of any sign of 

 the recent bursting of a follicle in any other of the seventeen cases 

 examined is in itself strong presumptive evidence that the two pro- 

 cesses are distinct. 



This result may be confidently asserted for Macacus rhesus during 

 the non-breeding season ; at the same time it must be remembered 

 that I have not investigated Macacus rhesus during the pairing 

 season ; probably at that time ovulation may be more frequent, and 

 may more often be coincident with menstruation ; but, however that 

 may be, menstruation occurs in Macacus rhesus regularly with- 

 out ovulation taking place, and my former views are confirmed, 

 namely, that ovulation does not necessarily occur during each men- 

 strual period, and that it is not necessarily brought about by 

 menstruation. 



I feel warranted in going further than this and asserting that the 

 regular occurrence of menstruation without ovulation, even though 

 it be in the non-breeding season, is sufficient evidence that ovulation 

 is a distinct process, and that it depends upon a law or laws other 

 than the laws which govern menstruation. 



The Discharged Follicle. The changes undergone by the discharged 

 follicles of Macacus rhesus during the non-breeding season are of 

 interest. Very shortly after rupture the follicle is pear-shaped, and 

 the place where rupture took place is to be seen in sections. 



The wall of the follicle is composed of branched cells which, along 

 the inner edge of the follicle, are longitu dinally disposed and form a 

 denser layer sharply defining the wall from the central cavity. 



The cavity contains a network of densely granular material and no 

 blood clot. 



