162 Transactions of the Society. 
finding its way into the reservior from the land, being carried there 
in contact with the seaweed used for manuring in Jersey. 
The size of the trematode is 5-6 mm. in length and 1-2 mm. wide ; 
it is of a light grey colour and fastens itself between the gill 
filaments. The shape can be seen from Fig 1, and the style of 
hooks on the disc, of which there are eight, from Fig. 2. So far as 
I am aware a complete life history has not been recorded. 
The effect on the fish is very marked. All fish picked up dead 
or dying and all fish removed by the net when attacked with this 
parasite show the gills almost bloodless and white ; an excess of 
mucus is exuded which appears to check to some extent the 
respiratory function of the gills. The fish on the whole shows a 
poor degree of nourishment, and probably is unable to get rid of the 
trematode when once badly infected. 
