CHAPTER VI 

 THE TUBAL HISTORY OF UNFERTILIZED EGGS 



When ovulation occurs without fertilization the liberated 

 ova enter the Fallopian tubes and eventually degenerate. 

 In most polyovular mammals the ova are shed surrounded 

 by an apparently sticky cumulus ovigerus so that a sort of 

 plug is formed due to the adhesion of the various separate 

 cumuli (see Plate VI, Figure 1). This cumulus mass remains 

 more or less intact for some time and then the cumulus cells 

 gradually become detached so that the ova finally float free. 

 The opossum (Hartman, 1925) and sheep (Clark, 1934) 

 appear to be exceptions since very few follicle cells surround 

 the newly shed ova. 



The chronology of egg passage in the tubes is best had 

 in the rabbit where ovulation occurs at 9 J^ to 10}^ hours 

 after copulation. 



The freshly ovulated ova enter the tubes and become 

 massed together, due to the adherence of the sticky masses of 

 cumulus cells. By 11 hours after copulation (about 1 hour 

 after ovulation) this mass of cumulus cells containing the 

 ova becomes securely lodged in the narrower portion of the 

 tubes just below the broad, fimbriated end. On washing 

 from the uterine end of the tubes this mass (see Figure 1, 

 Plate VI) is first ejected, then the washing fluid. The ova 

 remain thus massed together until about 17 hours after 

 copulation, an occasional ovum separating out of the mass 

 as early as 16 hours after copulation. Figure 2, Plate VI, 

 is the photograph of an ovum still embedded in the mass of 

 follicle cells at 16 hours after copulation. Figure 3 is the 

 photograph of the single one of the 10 ova removed at the 

 same time as that of Figure 2 that had separated out of the 

 mass. Note a number of follicle cells still clinging to the egg. 



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