George W. Bartelmez Bq 



a circular fragment (fig. 8*). Thus the vesicle seems, as ii were, to 

 nestle on the vitelline membrane itself and to develop with it.*"' 



So long as the ovule remains in the ovary, its external membranes 

 are so thick as compared to the exceedingly delicate vitelline mem- 

 brane that only the most persistent efforts suffice to separate them com- 

 L 9 H pletely from the vitelline membrane, without injuring it. It would be 

 well worth while to inquire into the relation between this membrane 

 and the inner surface of the external vascular membrane in the ovar- 

 ian ovule, how it comes about that the blood provides for the secre- 

 tion of the materials of the yolk. It is at least certain that the whole 

 inner surface of the vitelline membrane is, at this time, covered with 

 clear globules uniform in size, resembling blood corpuscles in form 

 and easily differentiated from oily yolk globules. 



The vitelline membrane while it is still in the infundibulum ap- 

 pears wrinkled and quite pliable so that the yolk, which is more viscid 

 and of a firmer consistency at this time, can take on the extremely 

 elongated shape necessary for it to pass the rather narrow canal of 

 the infundibidum to the oviduct Avith its looser walls, without any 

 tearing of the vitelline membrane. 



§7 

 Concerning the membranes of the calyx. 



Now while the ovarian egg is approaching maturity, the petiole 

 is elongated to almost lA ^ thumb's length, so that the most mature 

 ovum hangs down beyond the rest toward the uropygium and is 

 pressed into the wide open mouth of the infundibulum by the under- 

 lying intestines aided by the abdominal muscles.""' Then the stigma of 

 the ovum becomes more and more pale and while it is not thinned 

 out, it nevertheless becomes softer so that at last it is very easily torn 

 and releases the ovum. At this time, the external vascular membrane 

 contains a loose mesh of broad thin-walled veins, beginning on both 

 sides of the stigma with the branches disposed like very fine combs. 

 It appears to be a resorbing mechanism by which the tissue of the 

 stigma is gradually and imperceptibly dissolved and ovulation is 

 prepared for.""' 



The stigma does not first appear in the latest stage of the ovide but 

 it is already present as a fine, diill, whitish line in ovules of Vis the 

 full size which are still semi-transparent. The internal lamina of the 

 follicular membrane which adjoins the vitelline membrane is not of 

 a veil-like texture, as some would have it, and as it does indeed ap- 

 pear superficially, but it is very smooth and transparent and witliin 

 it minute corpuscles are scattered, which are perhaps glandular <.. 

 vascular tufts fairly regularly distributed. '"' 



