31 219 



conformity in the two families Melicertidce and Pedalionidce, have been developed inde- 

 pendentlj' of each other in fixed as well as in freeswimming organisms, or to conjecture, 

 that this unique combination, used under very different life conditions, suggests affinity 

 between the two families. Most probably the wheel-organ in the Melicertidœ is the best 

 for procuring detritus food, on the other hand it is rather weak as a swimming organ, 

 the result of this being the development of the jerking thorns and limbs which arc 

 more developed in the Pedalionidce than in any other family. The thorns are used to 

 alter the direction, which these footless species would otherwise have been unable to 

 do. In my opinion the Melicertidœ and Pedalionidce may be placed in the same di- 

 vision; to connect this with the Notommatidce is at the present time impossible. 



When DE Beauchamp claims that he has "montré" (1909, p. 29) that conver- 

 gence due to the same mode of nourishment enables us to demonstrate the conformity 

 between the two families Melicertidœ and Flosculariadœ I confess that, from my stand- 

 point, I can only see that, in these domains of investigation, whether our researches 

 are carried on in Nature or in the laboratories, we can never get any further than to 

 "enoiTcer", never to "montrer" anj^thing (vide pag. 40). 



The Flosculariadœ in my opinion form a rather heterogeneous group; as I how- 

 ever have never had an opportunity to see Apsilus and only on a journey a glimpse 

 of Stephanoceros, my views are of no value. I have thought that Microcodon was 

 in some way related to the Flosculariacea. Weber seems to have been of the same 

 opinion (1888, p. 18). De Beauchamp maintains, that its wheel-organ "se ratlache 

 facilement à celui de Cyrtonia par l'intermédiaire du genre voisin Microcodides." 

 I hope to return to this point later on. 



Chapter III. 



The Males of the Rotifera. 



Fam. Notommatidæ. 



As mentioned before I regard the fam. Notommatidæ as the most primitive of 

 all the families from which most, perhaps all, of the other families may be derived. 

 I regard it as quite impossible to indicate more thoroughly the closer relationship 

 between the many genera of Notommatidæ. In the following I draw upon the work 

 of Max Voigt (1912, p. 82). 



Nowadays very few males of the fam. Notommatidce are known. The males of 

 the genera Albertia, Drilophagas, Pleiirotroclia. Tlwonis, Taphrocampa. Monommalii, 

 Arthroglena, Distemma, Triopthalmus, Ologlena are all quite unknown; for a few of 

 them now one, now another, author has stated that he has seen "a glimpse of a 

 male", but this of course is of no scientific value. 



Only the males of the genera Cyrtonia, Proales, Diglenu, Copeus, Notommata and 



