THE EGO IN THE OVIDUCT. 



293 



(b). The yolk, or vitelline-ball, lies within this capsule, and 

 as it advances to maturity forms a more and more completely 

 pediculated growth, like a berry, of which every ovarium pre- 

 sents many in different stages (fig. 322). On that side of each 

 capsule, or berry, which is opposite the pedicle, a curved, 

 pretty broad, white streak is observed ; this is the cicatrice 

 (stiffi)Ki), (fig. 322, l\ which appears not to be vascular, for 

 although the blood-vessels entering by the pedicle form a 

 conspicuous rete with rhomboidal meshes on every other part 

 of the capsule, none are seen to cross or to penetrate the cica- 

 trice. The capsule is thinnest at this point, and the yolk is 

 here in most intimate contact, or even appears to be connected 

 with it (fig. 321, at the lower 

 part) ; the capsule at length 

 gives way, yielding in the line 

 of the cicatrice, and forming a 

 transverse rent with double 

 flaps, through which the yolk 

 escapes. The rupture of the 

 capsule in the line of the cica- 

 trice is easily effected by slight 

 pressure, even in ova that are 

 far from maturity (fig. 322, d) ; 

 it happens naturally to the ripe 

 ova after impregnation. When 

 the yolk has escaped, the capsule 

 which had inclosed it presents 

 itself as a hollow membranous 

 funnel, the calyx (fig. 322, d), 

 which remains hanging by its 

 pedicle, and shrivelling up or 

 shrinking into the stroma of the 

 ovary, soon leaves no trace of its 

 former existence. The detach- 

 ment of the vitellus is accom- 

 plished either by the perfected 

 growth of this body, its size 

 proving sufficient at length to burst the cicatrice, or by an 

 increase in the thickness of the capsule towards the pedi- 

 cle, by which the vitellus is forced as it were against the 



Fig. 321. Section of a yolk 

 almost ripe, included in its theca 

 and calyx : b, petiole or stalk 

 connecting the calyx with the 

 ovary ; a, thicker substance of 

 the calyx united with the theca 

 of the ovum ; c, vitellary mem- 

 brane ; d, germinal vesicle, which 

 by and by becomes the cumulus 

 proligerus of Bae'r, the nucleus 

 cicatriculae of Pander ; e, pro- 

 ligerous disc ; i, central cavity of 

 the vitellus, its duct proceeding 

 upwards. 



