THE UTERUS AND VAGINA. 307 



being the state of matters, we can understand how v. Siebold, to whom 

 we owe the first discovery of this peculiar structure,^ and his next 

 fonowers (among whom I was numbered at the time of the first edition 

 of this work) recognised in the products of the ovary only a germinal 

 vesicle, which was then generally believed to serve, as in other animals, 

 as a starting-point for the future egg. We need hardly add that v. 

 Siebold's idea needs no particular refutation at the present day. 



But the Cestodes have, in common with the Trematodes, not merely 

 a double egg-fOrming organ, but also a double female conducting ap- 

 paratus. The opinion formerly held that the so-called " uterus " of the 

 latter took part in copulation .as well as in the deposition of the eggs, 

 was erroneous, as has since been placed beyond a doubt by the well 

 corroborated observations of Blumberg and Stieda.^ The same error 

 prevailed, however, in regard to the female conducting apparatus of 

 Bothriocephalus until Stieda's researches proved the existence in this 

 case also of a special vagina beside the uterus." In the Teeniadse 

 the simultaneous presence of vagina and uterus had indeed been long 

 recognised, but the structure in this case seemed exceptional, since 

 in these animals the uterus is anomalous in being destitute of an 

 opening. 



Minot considers the presence of two kinds of female conductive 

 canals as such a characteristic and important peculiarity that he 

 proposes to unite the Cestodes and Trematodes into one group of 

 "Vaginiferce." But, on the other hand, it ought to be remembered 

 that a similar arrangement also occurs in other lower animals. The 

 female butterfiy, for instance, generally possesses a vagina, which is 

 separate from the oviduct, except for a narrow duct, and opens 

 exteriorly by a special opening near the latter — a state of affairs 

 essentially similar to that found in the so-called " vaginif erous " 

 Helminths. 



Although united in the same body, the male and female organs of 

 the Cestodes differ from each other, in becoming functionally capable 

 and mature at different periods of life. 



As I have long since shown, it is the male organs which first 

 develop and attain maturity, and that at a time when the female 

 parts are often imperfectly sketched out, so that in many cases one 

 feels tempted (Feuereisen remarks this especially in the Tcenia 

 setigera of the goose) to characterise the anterior joints as exclusively 

 male (Fig. 160, A). In studying the male apparatus, it is therefore 



* "Lehrbuoh der vergleichenden Anatomie der wirbellosen Thiere," p. 146, 1848. 

 " Ueber d. angebl. inneren Zusammenhang d. mannl. u. weibl. Organe d. Trema- 

 toden," MiiUer's Archiv f. Anat. v. Physiol, p. 31, 1871. 



» " Ein Beitrag zur AiiQigttiac^Tt^CmJ&^&mSi^vis,'' ibid., p. 194, 1864. 



