THE NEW GENEALOGICAL TREE 445 



ever been able to evolve from the larvae of the Tunicata? 

 The important discovery made by Kowalewski who succeeded 

 in proving that the Tunicata, which nobody knew ho\^' to 

 place into the animal system, are in reality genuine even if 

 retrograded Chordoma, has again shown the phyletic signifi- 

 cance of these larvae. These larvae have been used as a 

 representative example which could prove the theory of 

 recapitulation. These larvae do indeed recapitulate or repeat 

 something which is not, however, the adult ancestral form 

 but only its ontogenetic stage that has also preserved numerous 

 characteristics of the adult ancestral form. 



The whole organization of the Tunicata larvae is specific 

 and one-sided— we can mention here the fact that in them 

 the notochord occurs in the tail only, a body region which 

 had been newly developed by the Chordata— that there is 

 one form only which had evolved from them by way of 

 neoteny (similarly as has been the case with the Cteno- 

 phora and the Chaetognatha), i. e. the Larvacea, and nothing 

 else. This subtype of the Chordonia which exists as an onto- 

 genetic stage only points to an early existence of a general 

 type of the Chordata. BerriU (1955:3) good-humouredly men- 

 tions a statement regarding the book by Delsman that the 

 book should be confiscated and burnt; we can say on the 

 other hand about Berrill's book that it would be better if 

 it had not been published at all in spite of a number of sound 

 interpretations which appear in it, because of its basic idea 

 which is certainly wrong. The Vertebrata certainly did not 

 evolve from the planktonic tadpoles but rather from the 

 benthonic 'Vorm-like" Oligomeria. 



Neither can we consider as fortunate those suggestions 

 which try to derive the Chordonia from the planktonic 

 larvae of the Oligomeria, or directly from the so-called 

 Ambulacralia (Echinodermata and Enteropneusta). Like the 

 larvae of the Tunicata, these are again very specialized larvae 

 of the Oligomeria which could serve, at the most, as a start- 

 ing point for the evolution of some other planktonic form 



