Eugene Howard Harper 355 



That, as such, it is adapted to secure the safety of the egg is evident 

 from the thinness of the egg membrane when it leaves its tough ovarian 

 capsule and its consequent liability to be ruptured at this critical period. 

 Careful handling is necessary to secure the egg at this time. The cap- 

 sule of the egg splits along the pole opposite to its attachment in the 

 ovary. A gradual thinning out of the capsular wall occurs along the line 

 of splitting, causing a pale streak across the egg. The vessels of the 

 capsular wall are at this time highly charged with blood. Two such 

 pale streaks across the egg have been seen at right angles. During the 

 rupturing of the capsule, the egg bulges out in various places, producing 

 an irregular appearance with several protuberances. Inasmuch as the 

 wall grows quite thin during the process, it is quite possible that the 

 spermatozoa may be able to penetrate and reach the germinal vesicle 

 before the egg leaves its capsule. When the egg escapes, it is found well 

 surrounded by a thin albuminous liquid with which the body cavity at 

 this time is charged. It is like the albuminous secretion of the oviduct, 

 except that it is much thinner. This liquid serves both as a medium 

 for the spermatozoa, as stated by Balfour, and as a support to the egg 

 at this critical juncture, when it is invested by only a very thin membrane. 



The egg membrane or yolk membrane is about 3.5/i, in thickness. 

 The outer margin of the cytoplasm is somewhat denser and also takes on 

 something of the character of a membrane. In some preparations this 

 is found actually separated for a little way from the underlying cyto- 

 plasm. But for the most part it appears like a very thin non-separable 

 layer. 



The egg membrane appears structureless. It seems to .increase in 

 tenacity, since, when the egg is first set free from its capsule, it is very 

 easily ruptured. The flattening of the yolk from its own weight in the 

 fixing fluid is enough to cause the rupturing of the membrane. The 

 mcrease in tenacity later may be the effect of the deposition of closely 

 adhering layers of albumen. 



The egg is clasped by the funnel-like mouth of the oviduct, which at 

 this time has been observed to display active peristaltic contractions, as 

 if in the act of swallowing the egg. The contractions were confined to the 

 funnel portion of the oviduct. The fact as stated rests upon a single ob- 

 servation. As the transition from the funnel to the glandular portion 

 is abrupt, it would seem that the egg must be engulfed by muscular con- 

 traction, but after it is within the glandular portion of the oviduct it is 

 driven simply by ciliary action along its spiral course through the ovi- 

 duct, as has been stated by Cushny, 02, in regard to the hen's egg. The 

 peristaltic motions were sufficiently active to be unmistakable. The 



