LIFE HISTORY OF THE LIVER-FLUKE. 117 



or regular canals can be distinguished, but the ciliated infundi- 

 bula appear to communicate with an extensive system of 

 irregular lacunse between the cells of the body wall. 

 Numerous yellowish refractive granules occur in the 

 tissues of the sporocyst. or in the body cavity ; they are found 

 within the cells, but are especially numerous between them, or 

 on their surface. They are also present in large numbers in 

 the lacunse, and there frequently exhibit molecular motion, 

 thus showing that the lacunse contain a fluid of some tenuity ; 

 occasionally a whole group of them may be seen to move en 

 masse, or by careful pressure on the cover-glass may be made 

 to travel for a short distance along the lacunar passages. No 

 external opening of this system of passages can be seen, nor 

 any communication with the body cavity be clearly proved. 

 In the ciliated infundibula, however, there is present in the 

 lower wall of the space and close to the base of the flame- 

 shaped cilium, an elliptical structure, closely resembling that 

 which Fraipont has described in the ciliated infundibula of 

 certain other trematodes, as an opening into the body cavity. --. 

 This interpretation has more recently been called in question, / 

 but whatever the real nature of this structure may be, and it < 

 is difficult to see what else it can be, there can be no doubt 

 of its presence in the sporocysts. The yellowish granules 

 described appear to be excretory products formed within the 

 cells of the sporocyst and then ejected. They are partially 

 soluble in acids, leaving an organic basis. 



Wagener^ found in the sporocysts of Cercaria macrocerca 

 (the larva of Distoma cygnoides) vibratile lobules (Flim- 

 merlappchen) or ciliated spots, which he did not describe in 

 detail. Thiry^ described in the same sporocysts a system of 

 vessels, the branches of which had ciliated terminations open- 

 ing into the body-cavity. The vessels, however, were very 

 pale and diflicult to follow, and only in one instance, where the 

 animal was exceptionally transparent, did he plainly see the 

 whole system with its branches. The ciliated ends, on the 



• 'Beitrage z. Entw. d. Eiageweidewurmer,' p. 65. 



* ' Zeitsclirift fiir wissentscbaftliche Zoologie,' x, p. 272. 



