The Sexual Conditions of Myzostoma glabrum (F. S. Leuckart). 303 



of Artetnia form a case in point, for bere the male was utterly unable 

 to copulate with the female. 



Regarding the nature of the »oviducts« in the male Nansen's 

 argument might bave validìty, if an oviduct were always something 

 sui generis and not usually a derivative of some otber structure. 

 Elsewhere reasons bave been given for a belief that the »male 

 oviducts« are in reality functional nepbridia. This disco very, 

 published in the Z. Anzeiger 1894, bas been independently arrived 

 at by W. M. Wheeler. 



Agreement may be expressed with Nansen in the opinion that 

 some hermaphrodjtes in their youth perform exclusively male sexual 

 functions. Indeed, this is a corollary to the view bere taken of the 

 origin of hermaphroditism, for only the germinai cells of a young 

 individuai are likely to possess the property of becoming converted 

 into sexual products of the opposi te sex. 



Nansen's final contention that, if the dwarf-males were primor- 

 dial and the dioecious state the originai one, the bermaphrodites must 

 bave arisen from males and not from females, is uegatived by the 

 co-existence of true males. If males were absent, or if there were 

 males, females, and bermaphrodites within the limits of the species 

 M. glahrum^ the argument might be sustained. As matters are, it is 

 only another way of expressing inability to account for the presence 

 of »oviducts« in the male. As we bave seen, this is not at ali a 

 difficulty. 



It is uudoubtedly true, as Nansen insists, that the questions 

 involved in the origin and meaning of hermaphroditism are not yet 

 solved. 



The problem of the relationsbip, which may subsist between 

 hermaphroditism and parthenogenesis, is one stili awaiting solution. 

 Early in 1884 I was able to fertilise^ the eggs of a bermaphrodite 

 M. glahrum with spermatozoa from the testes of the same individuai. 

 The larvse produced developed quite normally for fi ve days, when 

 the usuai fate of larva? obtained in the ordinary way, i. e. by cross- 

 fertilisation, overtook them. 



From these experiments and from otber considerations there is, 

 as Roveri and others bave insisted, a strong temptation to regard 



1 These experiments were carried out with ali necessary precautions, such 

 as the use of clean dishes, filtered sea-water, etc. They bave more recently 

 been independently carried out by Wheeler with similar resulta. 



