DOMAIN OF EVOLUTIONARY HYPOTHESIS 135 



placed a still living genus the Aeluropus (from China) 

 because this animal, with regard to the advanced 

 development of its molars, represents a transitional 

 grade between the two genera which it is endeavoured 

 to connect together. Such anachronisms are to our 

 mind quite inadmissible. 



The same anachronism everyone is guilty of who 

 inserts the still living Rhyncocephalia (Hatteria) in 

 the same way, not only between genera, but between 

 two orders (Newts and Crocodiles), as a connecting link. 



4. Furthermore, the actually established continuous 

 reduction of the sexual generation in the higher plants, 

 determined by comparative botanists and advancing 

 from the Ferns to the Angiosperms, does not prove 

 by itself alone that Ferns, Gymnosperms, and Angio- 

 sperms form a genetic series. This is because also within 

 the Pteridophytes themselves there is determined a 

 similarly increased reduction, if we assume a suitable 

 association i.e. one which is based upon this character. 

 From the macrospores of the Water Ferns (e.g. Salvinia) 

 there is produced a very small female prothallus which 

 no longer leaves the spore integument ; the microspores 

 even only form a pair of cells ; * they are therefore, so far 

 as reduction is concerned, not behind the Gymnosperms. 

 Nevertheless, the Water Ferns remain true non-seed- 

 bearing plants, since the macrospores are thrown off 

 before the formation of the embryo and therefore do 

 not leave the mother plant as a so-called seed. 



* JS. Warming : Handbuch der systematischen Boianik, p. 144. 



