Dr Martin Barry's Researches in Embryology. 47 



along with others ; viz, that " when the discharge of the ovum 

 from the ovary is very near, that portion of the Graafian vesi- 

 cle directed outwards is seen to have been removed."* After 

 recording which, I gave a drawing of a Graafian vesicle "about 

 to discharge its ovum, that Graafian vesicle having been care- 

 fully dissected out of the ovarium, and so placed that the com- 

 pressor might act upon it laterally, when an appearance was 

 obtained which I cannot help believing to have presented the 

 orifice in question. \ And I have no doubt that in the Mam- 

 malia this orifice is intended as well for the admission of the 

 fecundating element, as also for the expulsion from the vesi- 

 cle in question (ovisac), while in the ovary, of the fecundated 

 ovum. J For my observations shew that fecundation of the 

 mammiferous ovum takes place in the ovary. § 



And here I am reminded, not only that the ovisac at its 

 origin, like other primary cells according to my observations, 

 is always elliptical and not round, but that as its size advances 

 (during which it becomes more spherical) it is often met with 

 somewhat tapered at one end ; which end is often found to be 

 the position of the minute ovum.\\ Now as possibly the ori- 

 fice in question may be intimated at an early period, and before 

 the ovisac becomes covered with bloodvessels to produce a 

 Graafian follicle, I recommend inquirers to seek for it chiefly 

 at the smaller end, which they will no doubt find directed 

 towards the surface of the ovary. 



I have just shewn that in Mammalia, when unfecundated 

 ova leave the ovary, the ovisac usually escapes with them. 

 It is deserving of notice that in this class of animals the 

 leaving of the ovary by fecundated ova seems to be always 



* " Researches in Embryology, Second Series." Phil. Trans., 1839, p. 317. 



t Phil. Trans., 1839, Plate 5, fig. 95. 



J See a drawing I gave of the ovisac with its orifice after the expulsion of 

 the ovum. Phil. Trans., 1839, Plate 5, fig. 98. 



§ It must not be inferred that my observations of Spermatozoa in the interior 

 of ova met with in the Fallopian tube, made me suppose fecundation of such ova 

 to have taken place after their expulsion from the ovary. ~ 



|| " Researches in Embryology, First Series." Phil. Trans., 1838, Plate 8, 

 fig 74 h. 



