J. D. F. Gilchrist 
319 
ment was repeated several times with intervals of three to seventy-two 
hours between times of feeding and dissection, and examination of all 
these confirmed the first experiment, though in the last case the empty 
cysts and well developed flukes only were observed. The confirmation 
of this by repeated experiments was necessary to prevent confusion with 
other cercariae and flukes, for the mollusc Tomichia, which harbours a 
cercaria as already mentioned, was occasionally found in the frogs, and 
there is another fluke, of a larger size and obviously different from that 
under observation, which is frequently found in the mouth of the frog 
just behind the tongue and still another occurs in the lungs. The life 
histories of the cercaria, of Tomichia and these flukes are other interesting 
subjects for investigation. 
The Egg Stage. The eggs were readily observed in the semi¬ 
transparent body of the adult fluke, and were frequently seen being 
discharged from the body; they were found also in the debris in the 
rectum. They were oval and varied in size from 0-34 to 0-25p, in length 
and from 0-18 to 0-16p, in breadth and were of a yellowish colour. 
The eggs were kept under varying conditions for some considerable 
time, but no sign of the emergence of an embryo was observed. It may 
be that no free swimming larva is developed and the eggs are swallowed 
by the snail. 
