'2a . A, OKA. 



of which is contimioiis with the tentactilaL' kiiiieii." In so fai- as tlie above 

 statements are concerned, a renewed investigation of the same species gave 

 exactly'the same results, as will be seen in the sequel. 



According to Cori, the body-cavity of i'olyzoa is divided by an incom- 

 pletely developed diaphram into t\^'o portions, the lophophoral cavity and the 

 body-cavity s. str., which corresiX)nd to the " Prosomhohle " and " Metasom- 

 holile " of Phoronis respectively. The nephridium consists of two short 

 ciUated tubes which open into a median unpaired bladder-like sac, that com- 

 municates in its turn with the exterior. " Die unteren Enden der beiden 

 Kaniile, der Nierenkaniile, miinden mit weiten Offnungen, den Nephrosto- 

 men, zu beiden Seiten des Ganglions in die Leibes-(Metasom- ) hohle ein." 

 The lumina of the median tentacles are prolongations of the lophophoral 

 cavit}^ being coimected with the latter by a sort of narrow chaimel running 

 beside the nephridial tubes. Such tentacles situated above the nephridium 

 are five in number (8. 2. 1. 2. 3) ; of these the three median ones stand in no 

 connection whatever with the latter organ, while the remaining two com- 

 municate with it by means of " Nebentrichter." The author remarks fur- 

 ther, that the epistoinial cavity open on both sides into the lophophoral 

 cavit}^ contrary to the statement of Braem. 



If we comj^are the above statements, we find that the chief points of 

 disagreement with regard to the structure of the organ are as follows. The 

 cavity inside the nephridial tubes is, according to Braem and myself, continua- 

 tion of the lophophoral cavity, while Cori regards it as a prolongation of the 

 body-cavity s. str. or the " Metasomhohle," if we adopt his terminology. 

 The lumina of a certain number of median tentacles open, according 'to 

 Braem and myself, into the cavity of the ciliated tubes, while Cori maintains 

 that they communicate with the lophophoral cavity by means of a canal out- 

 side the tube^. Cori found an unpaired median bladder, which neither Braem 

 nor I was able to discover. Lastly, Cori observed without difficulty the 

 external opening of the nephridium, which I confessed I could not find, al- 

 though I thought its existence most probable, while Braem states positively 

 that there exists no such opening in reality. 



