Vol. III. November, 1902. No. 6. 



BIOLOGICAL BULLETIN. 



THE FOLLICLE SACS OF THE AMPHIBIAN OVARY. 



HELEN DEAN KING. 



In 1738, Swammerdam (6) stated that just after the eggs of 

 the frog have been laid, one can find on the inner wall of the 

 ovary, " some empty and very delicate membranes which had 

 served to invest the eggs that had been already discharged from 

 the ovary. . . . These particles were most beautifully interwoven 

 with blood vessels to which they were fixed as to so many 

 stalks." Swammerdam does not give the origin of these mem- 

 branes nor does he state how the eggs pass from the ovary into 

 the body cavity. 



Over one hundred years later, Thompson (7) wrote that the 

 ovarian egg of the frog and toad " is surrounded by a thin vas- 

 cular sac formed by the dilation of the ovisacs which hang into 

 the general ovarian cavity. This capsule or ovisac is attached to 

 the rest of the ovarian substance by a broad band rather than by 

 a narrow pedicle ; and when the yolk or ovarian ovum is mature, 

 it escapes from the ovisac by the formation of an aperture in the 

 remote or free side of this capsule, somewhat in the same man- 

 ner as occurs in the calyces of the bird, but with a wider aperture. 

 Through the apertures of the general ovarian capsule the numer- 

 ous ova pass into the abdominal cavity." In thus stating that 

 the ovarian eggs first fall into the general cavity of the ovary and 

 later pass into the body cavity through openings in the ovarian 

 wall, Thompson is in agreement with earlier writers, Rathke (4) 

 and Lereboullet (3). More recently this view has been opposed 

 by Brandt (i) who examined the outer surface of the ovary of 

 Rana ternporaria as the eggs were about to pass into the body 

 cavity and found a round hole above each egg through which a 

 larger or smaller part of the egg protruded. This discovery led 

 him to state : " Es ist mithin klar, dass fiir jedes sich losende Ei 



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