356 



ASAJIRÖ OKA; OX THE SO-CALLED 



linino- of marine l^olyzoa take up foreign substances, and it seems very 

 probable that there exists some passage for the exit of these cells, pre- 

 sumably at the place corresponding to that in fresh-^vater forms. 

 Perhaps the semilunar pore of Mlcroporella discovered l3y Pergens 

 (18S9) might be of this nt-.ture. 



From the ol)servations summed up above, I come to the conclu- 

 sions, i) that marine P(3lyzoa have no structure comparable with the 

 ciliated tubes oï Vhijlaciola'umta, and 2) that the existence of a minute 

 poi-e ])utting the body-cavity in communication with the exterior is 

 highly probable. At any rate, a thorough investigation of marine 

 Polyzoa, with regard to this point is very much to be desired. 



Nepliridiuiii of EndoproctoKs Vohjzoa. 



It was FiAT>sciiEK (1S77) who first noticed the existence of the 

 nephridium in I'edicellitia. In his admirable paper "Über die Em- 

 bryonalent^wicklung und Ivnospung der Pedicelliua,'' this autlior 

 describes a fine ciliated canal situated in the body-cavity, in the 

 neighbourhood of the ganglion, with one end o])ening exteriorly, 

 but wdiose terminations conld not be determined positively. He 

 says: "Trotz Anwendung von stärkeren Vergriisserung (Hartn. 

 Imm. 10.) war es nicht möglich das hintere und vordere Ende 

 o-enau zu verfolgen. Doch schien mir das Hinterende mit einer 

 schw^achen Erweiterung in die Leibeshöhle zu münden, das vordere 

 Ende aber mit den dunkelkörnigen driisenähnlichen Mesodermzellen 

 in Verbindung zu stehen, die zum Theile Avenigstens eine reihen weiscï 

 Anordnung zeigen und in welchen ich mehrmals einen Kanal zu 

 verfolsren o'laubte : docli sind mir diese Verhältnisse sehr zweifelhaft 

 geblieben." Joltet wlio investigated this organ in PediccUina and 

 Loxmonia came to m<~)re s;itisfactory results. To cjuote his own 



