462 THE EVOLUTION OF THE METAZOA 



also be obtained by way of more detailed investigations of the 

 already known animal species and of their ontogenies. Finally 

 new viewpoints and methods of research can also be found 

 useful, especially those offered by the biochemistry. All these 

 elements combined can help us essentially to improve our 

 present animal system. Even now we can see the important 

 progress made within this sphere if we divide all the available 

 systematic suggestions into two main groups, i.e. a larger 

 group of systems which proposes a bifurcation in the evolution 

 of the Eumetazoa, and a smaller group of systems where 

 such a bifurcation cannot be observed. 



This state of affairs has been the main reason why I have 

 tried to make a corresponding suggestion before a competent 

 forum, the XlVth International Congress of Zoologists. At this 

 congress I (Hadzi, 1956a) proposed that a uniform systematic 

 scheme should be worked out which will be necessarily a 

 result of a compromise and which could serve well enough 

 in our practical didactic and operative work. Such a provisional 

 scheme reached as a result of a compromise must quite natural- 

 ly not prove to be an obstacle to our subsequent attempts to 

 establish a definitive natural system. The subsequent destiny 

 of my suggestion was entrusted to a special international 

 committee which is headed by a well known zoologist— yet 

 for reasons unknown to me this has been all that has been 

 done in this connection. A standardized system could also 

 serve as a basis for a review of all the valid animal names 

 w^hich was scheduled for publication at the occasion of the 

 XVth International Congress of Zoologists, to take place in London 

 (1958) simultaneously with a bicentenary of Linneus' work 

 System a naturae. 



Let us compare now two selected systems which can repre- 

 sent the two previously mentioned main groups. I choose 

 in this connection on one hand the system proposed by 

 L. H. Hyman (1948, part 1:38, cf. Fig. 61)— this system was 

 made, according to a statement by Hyman, partly with the 

 collaboration of Professor W. K. Fischer— and on the other 



