22 WRIGHT AND MACALLUM. [Vol. I. 



by neighboring cells, an appearance which is of interest in con- 

 nection with the ultimate terminations of the excretory system* 

 which we now proceed to discuss in the light of the important 

 modern researches on this point. 



According to Fraipont^ the finest canaliculi terminate in 

 ciliated funnels {entonnoirs cilUs). The base or expanded end 

 of the funnel is covered by a cap formed of a cell, which often 

 extends over the edge of the funnel on to its lateral surfaces. 

 The covering cell is convex superficially, and concave internally, 

 where the ciliated brush is inserted. An oval opening in the 

 lateral wall of the funnel allows a communication between it 

 and the lacunar spaces. The nucleus of the covering cell is 

 large, provided with a large nucleolus, and a part of the proto- 

 plasm of the cell on its concave surface is differentiated in the 

 form of a small disk, which does not stain, and on which the 

 ciliary brush is inserted. Fraipont made these observations on 

 Distomtim squamula and Diplostomum volvens. 



According toLooss^ the finest capillaries terminate blindly in 

 funnel-shaped expansions, which are formed of the capillary 

 wall. In the interior of this closed funnel, on the expanded end, 

 is inserted a brush of very fine cilia. He could observe no 

 openings in the lateral wall of the funnel. For these observa- 

 tions he employed Polystomiun ocellatum. In a Distomum he, 

 however, found branched cells, resembling the " Geisselzellen," 

 described by Pintner as occurring in Cestodes. These covered 

 the funnels, or rather the latter appeared to he in the cells, but 

 the contour of the funnels could not be determined. Conse- 

 quently Looss accepts Lang's view as to these structures, as they 

 are in Planarians; they are hollow cells, with cilia in their 

 interior. Poirier^ also found these funnels in Distomum clava- 

 tum and other species, but observed no lateral orifice in them, 

 such as found by Fraipont. Covering these funnels is a spher- 

 ical body, probably a cell, and the interior of the funnel is filled 

 with granular contents. It is also to be noted here, that Looss 

 corroborates the statements of the earlier observers, as to the 



' Recherches sur I'appareil excreteur des Trematodes et des Cestoides. Arch, de 

 Biologic, Tome I., p. 427. 

 ' Op. cii., p. 409. 

 '^ Op. cit.i p. 590. 



