Numerous specimens of this fluke were obtained on several occasions from domestic ruminants which were examined at Mukteswar. It has been ascertained that the infection occurs very commonly among goats and sheep, and occasionally also among bulls. Two buffaloes were also examined for infection with these flukes, but with negative results. The intensity of infection, particularly among ovines, is very great, several hundred specimens being obtained every time. Although these worms are found in all parts of the alimentary canal posterior to the oesophagus, the usual seat of predilection is the small intestine. On one occasion only were a few worms found in the bile ducts. It has been observed that the flukes die soon after the death of the host and begin to undergo post-mortem changes. For this reason it was often found difficult to obtain satisfactorily stained preparations of the parasites. Usually acid haematoxylin gave better results than the various carmine stains. The following description of the worms is based on the observation of several unstained and stained preparations and eight series of sections made through various planes.