464 ^' s. NICKERSON, 



Specimens when they are observed alive under compression. They 

 could be distinguished most clearly in the anterior end of the specimen, 

 where they could be seen to form distinct swellings at the extremities 

 of the finest tubules (PI. 30, Fig. 19). 



The view which I could get of them was not however such as to 

 enable me to enter at all into the discussion of the question of the 

 method by wliich the tluid passes from the tissue spaces into the 

 lumen of the tubules. 



The capillaries also are for the most part distinguishable only 

 in the living specimen. They are exceedingly fine tubules, having a 

 more or less dendritic arrangement, and terminating in flame-cells ; 

 never, so far as I have observed do they form anastomoses with one 

 another. Whether the whole excretory system of one side of the body 

 is entirely separate from that of the other side even to the cai)il- 

 laries, I cannot state positively but I very strongly believe that such 

 is the case. Neither am 1 certain whether in Stichocotyle the capil- 

 laries are arranged in groups in diti'erent parts of the body. In the 

 anterior end of the body they could be seen in the living worm to 

 be quite numerous, whereas in the region a little farther back I was 

 unable to distinguish them. This may have been due, however, to 

 the greater opacity of this portion of the body caused by the presence 

 of the great lateral excretory trunks with the concretions contained 

 in them. The arrangement of the branches of the collecting tubules, 

 as shown in preserved specimens and represented in PI. 31, Y\g. 23, 

 suggests such a grouping. A sketch of the capillaries seen at the 

 anterior end of the worm is given in PI. 30, Fig. 19. 



The walls of the capillaries appeared to be lined with a coating 

 of exceedingly short, fine cilia. This observation is not in accordance 

 with those reported by students of other allied Trematodes, nor with 

 observations of my own upon these tubules in other Trematode larvae; 

 nevertheless I believe that such cilia are present in Stichocotyle. 



The collecting tubules form a well develoi)ed system, within 

 each of the lateral halves of the animal. They can be very cle;irly 

 seen in the living worm observed under a compressor, thougli their 

 distribution and connections can be iiiuch more satisfactorily made 

 out in prejiarations of the whole worm. They lie upon the dorsal 

 side of the large lateral vesicles, whose convolutions they follow 

 closely, and may be traced continuou.sly from near the tail end forward 

 to the point at which they open into the large lateral vesicles. 

 This point is far forward near the head end, but may be somewhat 



