558 H. p. KJERSCHOW AGERSBORG 



membrane is prominent, but unlike the condition here, where 

 it seems to be granular, the appearance of the basement 

 membrane in the ciliated cells of the renal syrinx is a con- 

 tinuous, non-granular line, or the granules if present are fused. 

 However, this may also be the condition in the intestinal 

 cells (PI. 33, figs. 46, 47), reflecting, perhaps, the fact that the 

 bringing out of certain cytological features depends, at least, 

 on two things : (1) the physical condition of the organism 

 at the time of killing, (2) the method and kind of chemicals 

 employed in the killing. Another differential feature of the 

 ciliated cells of this organ, is, as pointed out above, the indepen- 

 dent arrangement of the cilia. That is, the cilia are not mingled 

 with the cilia of neighbouring cells, as in the case of the intestine. 

 Still another feature is the size of the cilia both in length and 

 diameter. This specialization of the cilia may point toward 

 a special function of the organ. For example, it may be that 

 of creating a suction within the organ in order to draw the 

 pericardial fluid toward and through the cyncitial plate. The 

 cyncitial plate, then, with the action of the specialized cilia 

 of the plicae may function as an extracting organ, and one may 

 expect this process to be that of ridding the pericardial fluid 

 of waste. This is also the opinion of Hancock (1864 : 520) 

 for Dorids. 



Von Jhering (1876 : p. 49) applies the name " Pericardial- 

 trichter ' to the renal syrinx. By this name its function is 

 indicated also. The case in question is that of Tethys, 

 for which the author finds that the syrinx communicates with 

 the lumen of the ureter : ' ... in weiter Communication steht, 

 andererseits durch eine kleinere runde Oeffnung mit der Peri- 

 cardialhohle zusammenhangt. Die letztgenannte liegt in einer 

 Membran, welche quer zur Axe des Pericardialtrichters steht 

 und sein Lumen von dem des Pericardium trennt. In dieser 

 Membran liegen um die Oeffnung herum zahlreiche ringformig 

 angeordnete Muskelfasern, die also einen Sphincter bilden durch 

 welchen die Communication zwischen Niere und Pericardium 

 nach Belieben aufgehoben werden kann.' 



Bergh (1884 a: 76) does not describe the exact relationship 



