120 OVULATION AND EGG TRANSPORT 



d. A portion of the coelomic epithelium, liver, and oviduct containing eggs should 

 be studied histologically to identify cilia. Such tissue should be compared 

 with similar tissues of the non-ovulatlng female and of ein adult male. 



6. The distribution of Jelly and the development of eggs from different parts of 

 the oviduct should be studied. 



DISCUSSION : 



The rupture of the ovarian follicle of the Amphibia is quite different from that of 

 Mammals. The function of the pituitary In the initiation of this process is not definite- 

 ly known, although it is invariable. The dose of the anterior pituitary hormone In am- 

 phibia regulates the number of eggs released, so that ovulation is not an all-or-none 

 phenomenon. It would be of Interest to determine whether the pituitary hormone acts 

 through the circulatory or the sympathetic nervous system, of both, or whether it might 

 act directly. 



The fact that the Jelly-free body cavity egga cannot be fertilized and will not 

 develop has been a slight deterrent to experimental procedures with amphibian eggs for in 

 many experiments the Jelly must be removed. Whether the answer to this dilemma rests 

 within the Jelly, or with changes In the egg, or with both, has not yet been determined. 



The nucleus of the ovarian egg is In the germinal vesicle stage, prior to any matura- 

 tion divisions. This germinal vesicle breaks down at the time of ovulation and as the egg 

 passes through the upper third of the oviduct the first polar body la given off. The 

 second maturation division begins immediately and by the time the egg reaches the uterus 

 the metaphase of the second maturation division has been achieved. The egg remains in 

 suspended metaphase until It is either fertilized or disintegrates. 



Coelomic cilia in the Amphibia represent a clear-cut secondary sexual character, 

 developing only in the female after the attainment of sexual maturity and the elaboration 

 from the ovary of an ovarian hormone. There is some evidence that theelin will cause the 

 development of cilia in mature males. The function of the coelomic cilia of the female is 

 no doubt for the transport of the egga to the ostium and through the oviducts to the uteri, 

 but they are present and active at all times. The coelom and genital ducts may therefore 

 function also as accessoiy excretory organs. 



During sexual activity, normal or induced by anterior pituitary hormone, the oviducts 

 are much enlarged due to imbibition and to the secretory activity of their glands. Ovi- 

 ducts of non-ovulating frogs will transport eggs and deposit Jelly, but do it in an irregu- 

 lar manner. Such eggs are ferlilllzable. 



CONCLUSION : 



Through a simulation of the breeding activity of the frog by the injection of the 



mature female with the anterior pituitary hormone, it is now possible to study the entire 



reproductive process from the rupture of the ovarian follicle to the appearance of the 

 fertillzable egg in the uterus. 



"The development of an egg into a finished embryo is 

 essentially due to factors residing in the egg itself. 



Roux 



