PREVIOUS INTERPRETATIONS OF CNIDARIA 171 



conditions had been prepared as early as in the Anthozoa which 

 have become generally characteristic of Scyphozoa and Hydro- 

 zoa. It is in agreement with the way of life and with the type 

 of feeding that the peristome evaginates into an oral cone, a de- 

 velopment which begins to prevail over the opposite trend, 

 i.e. over the invagination of the oral area. 



The oral cone, as a process of the oral area, possesses a well- 

 developed muscle system (externally these muscles are placed 

 longitudinally, internally they are placed transversally) ; by 

 means of these muscles the oral cone is enabled to move in 

 all directions, as w^ell as to contract and to extend, always with 

 the oral opening at its top. The oral cone, or the manubrium 

 of medusae, develops again into a gripping organ; frequently 

 it can even take over the function of tentacles which makes 

 macrophagy possible and this can finally lead to a total 

 loss of tentacles. Not a single trace of an ectodermal gullet 

 can be found either in Scyphozoa or in the Hydrozoa. The 

 entoderm of the anterior intestine— which passes over into 

 an ectoderm exactly at the oral margin— is richly equipped 

 with gland cells which help swallowing and digestion. 



It has already been mentioned that among the Cnidaria an 

 ectodermal gullet as well as true sarcosepta can be found in 

 Anthozoa only as special elements of their digestive system. 

 Neither the one nor the other of these two elements can be 

 found in the most primitive Turbellaria, even if both of them 

 can be found to a certain degree in a large number of Turbella- 

 ria. Certainly, we do not find here sarcosepta but rather a ge- 

 neral and distinct trend of their intestine to form diverticula. 

 The oldest fossilized Anthozoa possessed well developed sarco- 

 septa, even if these cannot be seen; the fact, howxver, that 

 they possessed sclerosepta w^hich alone could be fossilized is 

 a certain indication that they also possessed sarcosepta which 

 could not be preserved by fossilization. The supposed presence 

 of sarcosepta allows us to consider that these primitive 

 anthopolyps had already had a pharynx. The supposed transi- 

 tion from Turbellaria— with intestinal diverticula— to antho- 



