no OVULATION AND EGG TRANSPORT 



OBSERVATION AND TABULATION OF DATA: 



1. A complete description of the rupture and the emergence of the egg from its follicle 

 should be made and compared with descriptions for the same process in mammals. 



2. The relationship of ovarian movements should be determined by comparing such move- 

 ments with those in a non-ovulating ovary. 



3. Analysis of the effects of insemination of body cavity eggs should be made and should 

 be supplemented with a cytological study using both Heidenhain's Iron-haematoxylin 

 and Feulgen techniques. 



4. 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-ovulating female and of an adult male. 



5. The distribution of jelly and the development of eggs from different parts of the ovi- 

 duct should be studied. 



DISCUSSION: 



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

 mals. The function of the pituitary in the initiation of this process is not definitely 

 known, although it is invariable. The dose of the anterior pituitary hormone in amphibia 

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

 enon. 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 eggs cannot be fertilized and will not develop has 

 been a slight deterrent to experimental procedures with amphibian eggs for in many ex- 

 periments 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 maturation 

 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 is given off. The sec- 

 ond 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, devel- 

 oping 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 de- 

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

 no doubt for the transport of the eggs 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 accessory excretory organs. 



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

 are much enlarged due to imbition and to the secretory activity of their glands. Oviducts 

 of non-ovulating frogs will transport eggs and deposit jelly, but do it in an irregular inan- 

 ner. Such eggs are fertilizable. 



CONCLUSION: 



Through a simulation of the breeding activity of the frog by the injection of the mature fe- 

 male with the anterior pituitary hormone, it is now possible to study the entire reproduc- 

 tive process from the rupture of the ovarian follicle to the appearance of the fertilizable 

 egg in the uterus. (See references on pages 101-103) 



