BY F. P. SANDES. 397 



under ordinar}^ circumstances ensue. With regard to the corpus 

 luteum atreticum, the failure of extrusion of the ovum is an 

 accidental departure from the normal, so that in the ease of 

 follicles which have attained a certain stage in their process of 

 ripening, they possess suthcient energ}' to proceed with the forma- 

 tion of a corpus luteum atreticum, thus trying to carry out their 

 function. And here it is interesting to observe tliat occasionally 

 the ovum of the atresic follicle itself undergoes a kind of partheno- 

 genetic division, which seems to be an attempt on its part to carry 

 out its destiny. 



To sum up, it maybe stated as probable, firstl}-, that the corpus 

 luteum is a glandular structure with an internal secretion- and 

 secondly, that it influences the genital organs and the organism 

 generally and prevents ovulation during pregnancy, and tempo- 

 rarily if pregnancy does not occur. 



Summary. 

 The chief conclusions arrived at in this investigation on the 

 corpus luteum of Dasynrus viverrinus are : — 



(1) The characteristic cells of the corpus luteum are formed 

 by hypertrophy of the cells of the membrana granulosa. 



(2) The theca interna folliculi is rudimentary and forms only 

 the vascular connective tissue of the corpus luteum. 



(3) The corpus luteum atreticum is formed in the same way as 

 the corpus luteum verum. 



(4) Other atresic follicles are reduced to fibrous tissue or 

 remain cystic. 



(5) The corpus luteum is probably a gland with an internal 

 secretion of use in the organism. It has the function of stopping 

 ovulation during pregnane}^ and at the oestral periods. 



Bibliography from 1895 onwards. 

 AzEVEDo Neves. — " Contribucao para estudo do ovario." Thesis. Lisbon, 



1901 (cited by Limon, v. i,). 

 Beard, J. — (1) "Ehythni of reproduction in Mammalia." Anat. Anz. Bd. 



14, 1897, pp. 97-102. 

 (2j " The Span of Gestation and The Cause of Birth." 



