The Sexual Conditions of Myzostoraa glabinm (F. S. Leuckart). 297 



cells of spermatozoa (spermatogonia) or by developing spermatozoa 

 themselves. 



The appearances seen in the sections of the forms of tab. 2 

 revealed another fact, viz., that the hermaphrodites are also pro- 

 tandrous', a fact, which is true of many, if not of ali, herma- 

 phrodites. 



Amoiig the forms of tab. 2 not a single individuai, which would 

 a priori^ from its position on the disc, bave been regarded as probably 

 hermaphrodite, turned out to be a male. In ali, in addition to male 

 Organs, developing eggs could be detected. 



It thus appears that on the most essential points botb of 

 Nansen's contentions are uegatived by the facts. The dwarf males 

 are neither young protandrous hermaphrodites, nor do they eontain 

 the slightest trace of true female Clements. Moreover, the places 

 usually occupied by such female cells (i. e., as will presently be 

 shown, along the dorsal or htemal wall of the body-cavity) were filled 

 by sperm-mother-cells, or by developing spermatozoa (fìgs. 7,8, and 13). 



Nansen cites fig. 15 pi. 2 of his memoir in evidence of the 

 presence of rudiments of ovaries in some complemental males, and 

 says (6, p. 79): — »in brancbes of the uterus are situated some organs, 

 similar to those in the hermaphrodites, and which are probably traces 

 of ovaries« (comp. fig. 14). 



Since then, in a paper to be cited subsequently, Wheeler (8) 

 has shown that these deeply-staining organs of the hermaphrodites 

 represent ovaries. He considers that these organs of Nansen are 

 the sole ovaries, a conclusion which is disputed on grounds of Ob- 

 servation by Prouho (7) and myself. Whilst there appears to be no 

 doubt as to the ovarian nature of Nansen's organs in the herma- 

 phrodites, I must contest the correctness of Nansen's view, which is, 

 as will be seen anon, also supported by Wheeler, that they re- 

 present ovaries in the dwarf-males. In no true dorsicolous form bave 

 I been able to find any evidence in support of their ovarian character, 

 and in ali my numerous preparations of such individuals they bave 

 the appearauce of testes. 



Nansen also adduces the presence of »oviducts« in the dwarf 

 males as a further argument in favour of his view. This fact has, 



1 For 3Iyzostoma this was first established by von Graff (Challenger Rep. 

 Voi. 10 pag. 43). Nansen on pag. 59 and elsewhere in his memoir has also 

 expressed agreement with this view. 



