06 A. OKA. 



by him. In reality, tlio short tubes do not open into the body-cavity at 

 all, l)nt eiid blindly in a large cell with a set of long cilia in a cavity of 

 its cell-body, as was already pointed out l)y Foettinger.t I regret 

 having overlooked such an important piece of work as his. At any rate 

 the nephridium of Endoprocta is constructed entirely upon a different 

 plan from that of the Phylactolaeraatons Polyzoa, so that the two organs 

 ought by no means to be compared with each other. While the nephri- 

 dium of the Phylactolaematous Polyzoa is formed by the differentiation 

 and folding of the epithelial lining of the body-cavity and serves as the 

 passage of exit for the leucocytes, that of the Endoprocta much resem- 

 bles in structure the excretory organs of parenchymatous worms or the 

 pronephros of certain molluscan larvae. In the nephridium, therefore, 

 we do not find one of the points of agreement of the two main divisions 

 of Polyzoa, as I suggested in my last paper, but rather a sign of the 

 comparative remoteness of their relationship. 



* Ortj;'n,ne segmentaire des Bryozoain^s Endoproctes. Arch, de Zool. oxper. YIII. 

 t Sur Tanatomie des Pedicellines de la cote d'Osteude. Arch, de Biol. YII. 





