NEW INTERPRETATION OF CNIDARIA 301 



concept (naturally not as the first zoologist, yet quite independ- 

 ently) neither by way of a study of Infusoria or of Turbellaria, 

 but rather after a protracted study of problems connected 

 with the Cnidaria. I am therefore happy when 1 see other zoo- 

 logists who work in other special fields of interest, such as. Otto 

 Steinbock, a prominent expert in Turbellaria, extend their inte- 

 rest in the direction of the present study. I am also very 

 happy to see that Hanson wrote his study mainly from the 

 point of view of an expert in Protozoa, even if we do not 

 agree in every detail. 



There are mainly three points in which Hanson tries to 

 improve and perfect my concept in order to make it more 

 acceptable, after he had submitted it to a detailed critic- 

 ism. 



Hanson wishes first that something more definite, more 

 real, could be found instead of the too general name of the 

 infusorial ancestors of the Acoela which were designated as 

 "infusorian, or ciliate-like" animals. Hanson has selected the 

 "pleurostomatous gymnostomes" from the group Euciliata 

 which is rich in forms, more precisely from the subgroup 

 Holotricha which even now possess the most primitive 

 characteristics. These "pleurostomatous gymnostomes" are on 

 one hand homogenous, and on the other hand they have 

 remained most similar to the Acoela. Hanson selected as their 

 representatives the two genera Kemanella and Dileptus. It is 

 quite natural that the two forms which are genuine (as well 

 as recent 1) Euciliata have all those similarities with the Acoela 

 that can be generaly found among the Euciliata, even if 

 they belong to the more speciaUzed forms. We are therefore 

 interested in those pecularities of these two genera of EuciUata 

 which could justify us to suppose that they are more closely 

 related to the Acoela than are the remaining Euciliata. Such 

 peculiarities could be the un-differentiated character of cilia, 

 the primitive conditions of the cytostome surrounding, and 

 above all the pluraHty of nuclei, thus of karyons, whether 

 they be somatic or generative. 



