36 A. OKA, 



animal, as well as to the oxtont of the influence, which ''ifferent modes of life 

 exercise upon the organisation. 



The Eetoproctoas and Eudoproctous Polyzoa agree in the following 

 ])oint3. They are all small sedentary animals, generally united into colonies, 

 with ciliated tentacles and with the degestive canal bent in the form of the 

 letter U. They are all provided with a single nervous ganghon. These were 

 the characters that made the older zoologists unite them in one group. In 

 the nephridiam, we find one character more that would make the union still 

 closer. Both the Phylactolaematous Ectoprocta and the Endoprocta are 

 provided with a special oi-gan serving for the exportation of leucocytes laden 

 with excretory products. 



While I thus maintain the genetic affinity of Entoprocta and Ecto- 

 procta, I do not mean in the least to undervalue the points of agreement l)e- 

 tweeu the latter and other forms of animals, such as Plioroui?;. The resem- 

 l)lance which wo find between PJinrojiis aiid Phylactolaematous Polyzoa is 

 indeed so great that we are forced to regard them as very near relatives. It 

 is a reasonable proceeding, when Hatschek puts these a.ninials together with 

 Hrachiopoda in the cladus Tentaculata, corresponding to MoUuscoidea of 

 other authors, but what T want to point out is that the Endoprocta should be 

 placed somewhere in or near this group as a degenerated or simplified form. 

 Whether tliis suggestion is really justified or not, I do no venture to state at 

 present, but hope to be al)le to ascertain after a study of the nephridial organ 

 of Endoproctous Polyzoa. 



EXPLANATION OF PI. IX. 



g. ganglion. n. nepliridium, 



gc. ganglionic cavity. 1. lophophoral cavity. 



ep. epistomo. 1, 2, 8, 4, 5. tentacles, 



epc, epistomial cavity. 



oe. oesophagus. 



Fig. 1-4. Cross sections of polypide. Winkel 1 x V. The dotted Hues 

 in iig. 1 show the extent of the diaphragm on the oral sic]e. 



