THE MOST PRIMITIVE METAZOA 65 



A difference of opinion arose between Haeckel and other 

 workers over the structure of the Physemaria. Saville Kent in 1878 

 from studies of both living and fixed material decided that 

 Haliphysema was no sponge but instead a foraminiferan rather 

 like Euglypha. He was unable to see any of the internal details 

 described by Haeckel. A controversy soon arose between Haeckel 

 and Saville Kent and it was left to Ray Lankester, as a friend of 

 Haeckel, to enter the controversy in the role of adjudicator. 



Lankester asked Saville Kent for specimens of Haliphysema 

 and then examined them both alive and in the fixed and stained 

 condition. After considerable examination Lankester (1879) 

 decided that Saville Kent was perfectly correct in his assertions 

 and that the specimens were clearly those of a foraminiferan. But 

 the matter did not end there. Lankester ingenuously decided that 

 the answer to such a controversy was extremely simple. He sug- 

 gested there must be two different genera of animals which from 

 the outside looked exactly alike but one of these had been studied 

 by Professor Haeckel whilst the other had been studied by Mr. 

 Saville Kent. Lankester had no doubt that the isomorph studied 

 by Haeckel would have the structures that Haeckel had described 

 and he hoped that Professor Haeckel would supply him with some 

 specimens. It does not appear that such specimens were ever 

 sent to Lankester. 



Perhaps something should be said in Haeckel's defence. In a 

 recent paper on Haliphysema tumanowiczii, Hedley (1958) describes 

 the way in which the protozoan often picks up sponge spicules 

 and covers itself with these. Also certain individuals were 

 multinucleate, a condition which in certain circumstances might 

 be confused with some of the conditions described by Haeckel. 



Haeckel continued to believe in the importance of the Physemaria 

 though he thought that the Gastrula was more important (1899). 

 He derived all the Metazoa from the Gastrula and stated, " I 

 regard the Gastrula as the most significant and important 

 embryonic form in the whole animal kingdom. It occurs amongst 

 the sponges, Acalephe, the Annelida, Echinodermata, Arthropoda, 

 Mollusca, and the Vertebrata as represented by Amphioxus. In 

 all these representatives of the most various animal stocks, from 

 the sponges to the vertebrates, I deduce, in accordance with the 

 Fundamental Biogenetic Law, a common descent of the whole 



