J. D. F. GtIlchrist 
O i ^ 
badly infected with the parasite. Meanwhile the lake had been rapidly 
drying up, and the snails were then found at the roots of water plants, 
or in the muddy and grassy bottom. Only one or two per cent, of 
the snails had a healthy liver, unattacked by parasites. The infection 
however did not seem to affect their reproductive powers, as numerous 
clusters of 20 to 30 eggs were deposited on objects in the vessel, in which 
the snails were kept. Later on all snails found proved to be infected, 
and towards the end of February and beginning of March, the lake 
dried up, and no more snails were to be found even in places with 
water. 
Redia. The smallest free redia had a well developed muscular 
pharynx, an anterior ring,, sometimes assuming the appearance of four 
blunt projections, and two prominent posterior projections. One was 
observed to escape from the parent redia (about three times its size) 
at a point behind the anterior collar. Another free redia, of about 
the same size as this small one, had the alimentary canal well filled with 
food. The full grown rediae were of a brick-red colour. 
Cercaria. The mature cercariae are clear and transparent by trans¬ 
mitted light, white by reflected light. They are often observed to be 
very active within the rediae, twisting about and passing from one end 
to the other. When they escaped from the redia they were well 
developed with a flattened body. The outline of the body varied much 
according to its active movements. 
The cercariae, when they have escaped from the body of the snail 
and are free in the water, are very active, and keep the body flexed so 
as to assume an appearance like a comma or point of interrogation. 
They measured in the living state when stretched out 0-19 by 0-17 mm. 
Another, circular in form, measured 0T8 mm. in diameter. These 
measurements it may be noted are much less than those of the 
cercaria of Distoma hepaticum, which are given as 0-28 by 0-23 mm. 
The posterior sucker is frequently thrust out to a considerable extent, 
even occasionally assuming a pedunculate appearance. At each side 
of the anterior end of the body there was a slight projection or shoulder, 
but no spines were seen either on the head or body. It differed in this 
respect from the cercaria of D. echinatum. These free cercariae were 
afterwards procured in thousands by keeping 20 or 30 snails in a dish 
of water for a few hours. At first they crowded towards the light, but 
later on swarmed towards the spot furthest from it. This movement 
was very decided and comparatively rapid, about 6 inches in a minute. 
They did not seem to be attracted by any grass or water weeds placed 
