( 401 ) 



"Markstrange" of tho ovarium (Mimai.kovics), or as tubules of the 

 mesonephros grown into the tissue of the testicle (Kollmann) ^) is 

 not found in marsupials. If, during further developmeut a network 

 resembling the rete testis, arises in the marsupial testicle, it must 

 be considered as a i)art which appears quite secondary. 



The connection of the testicle and epididymis is not caused by 

 a number of tubules of the mesonephros, transformed to vasa effe- 

 rentia, but by a single tube which must be considered as a part of the 

 Wolffian duct. For the conception that the connecting tube really is 

 the Wolffian duct, tlie phenomena of development in the female sex 

 can be cited together with those in the male animals. In the marsu- 

 pials all the tubules of the mesonephros are i-educed to minimal 

 rests (vasa aberrantia). In the mass of tissue, which represents the 

 so-called epididymis of these animals, a great number of tubes arise 

 secondary, which afterwards probably possess as epididymis tubules 

 the same function as the coni vasculosi in tlie epididymis of other 

 mammals. 



To explain the ditTerences in the connection of the testicle and 

 epididymis in marsupials and in other mammals, the following con- 

 siderations seem to me to be of importance. 



About the changes, which the mesonephros undergoes, by its con- 

 nection witii the testis, which connection furnishes the later vasa 

 eiferentia testis, we read the following in the extensive investigations 

 of CoERT^): In the proximal part of the Wolffian body where the 

 Malpighian bodies are connected with the blastem of the rete 

 testis, we see the glomeruli and the inner epitlioHuni of the capsules 

 disappearing gradually ; after which the outer walls of these capsules 

 form the blind extremities the mesonephridial tubules. The epithelium 

 of the mesonephridial tubules also begins to have another aspect. 

 Two kinds of processes occur here together: a number of epithelium 

 cells are pushed out into the lumen and are destroj'ed, while on the 

 other hand many new cells are foi-med (mitosis). With this the cells 

 get another appearance both as concerns the nucleus and the proto- 

 plasm. The result is that at last the tubules of the menonephros are 

 surrounded all over their extent, which formerly was not the case, by 

 an uniform epithelium, formed by cylindrical cells, the nuclei ranged 

 regularly at the basis of the cells. Whether the connection of these 

 tubes with the Wolffian duct always remains unchanged during those 

 transformations or is perhaps broken off and afterwards re-established 

 in another place I have not been able to investigate. 



1) Kollmann, Lehrbuch der Eutwickelungsgeschiclite des Menschen. 



2) I.e. p. 96. 



