The Tunicates, or Ascidians 48 i 



"According to the most common view Appendicularia is 

 not an ancestral form at all, but is the tadpole stage of the 

 Ascidiacea that has failed to undergo metamorphosis and has 

 become sexually mature in the larval condition, as the larva 

 of certain Amphibians and insects are known to never pass 

 into the adult state but reproduce their kind sexually in the 

 larval condition. By this view the tadpole of such Ascidian 

 as Ciona, for example, represents more closely the common 

 ancestor of the group than does any other form we know. This 

 view is especially defended by Professor K. Heider and Dr. 

 Arthur Willey." 



