24 WRIGHT AND MACALLUM. [Vol. I. 



thereby so altered as to call forth the most vigorous activity of 

 the cilia of the funnels, thereby rendering them more easily 

 seen. When the specimen is dead, but before the tissues be- 

 come clouded, the movements of the cilia slacken very much, 

 and one is then permitted to study its nature. A single move- 

 ment of each cilium consists of a wavy motion passing from its 

 inserted to its free end; i.e.y down the cavity of the funnel. 



We have observed the presence of bunches of cilia in the 

 larger trunks, especially immediately in front of the contractile 

 bladders. Sometimes these bunches are long and slender, at 

 other times quite thick. From what they take their origin it is 

 difficult to say. In two cases they appeared to arise from a cell, 

 or protoplasmic structure, embracing the canal. Sections of 

 hardened specimens have not, in the most diligent search, be- 

 trayed the presence of cilia in the larger canals, so' that nothing 

 definite can be said corroborative of what fresh specimens 

 show. On the other hand, in the same preparations, one some- 

 times sees an excretory vessel apparently perforate a cell ; but 

 no cilia could be observed in the cavity of this perforation, 

 although their presence is extremely easy to overlook. 



As in the ciliated funnels, so in the larger trunks of the 

 excretory system, the ciliary action is best seen only under ex- 

 traordinary conditions. It is noticeable, also, under like circum- 

 stances, that the larger trunks, although fully dilated, yet contain 

 very rarely any of the granules which gorge the smaller ves- 

 sels. An explanation of this is possibly that pressure from 

 the cover-glass prevents the entrance of these granules into the 

 larger trunks. On the other hand, it is not certain whether the 

 distention of these trunks is due primarily to the excess of 

 fluid which they contain, or to the relaxation of their elastic 

 walls. In the so dilated vessels were several times observed 

 monad-like organisms, always with a rotatory movement. 



We have now to describe structures of paramount interest in 

 connection with the excretory system of Sphyranura, and 

 which have not, we believe, been observed in other Trematodes. 

 These bear most resemblance in form to the plant-like cells of 

 certain Trematodes, as described by Leuckart and others, but 

 beyond this point the similarity ceases. 



These structures are cells of the character and appearance 

 presented in Figs. 12, a, b, c, which represent them both in the 



