GROUSE DISEASE 201 



Any attempt to control their number and their 

 activity must depend on our knowledge of their 

 life-history, hence the stress which has been 

 laid on the external parasites which may act as 

 the second or larval host of some of them. 



At the time the recent Grouse Disease In- 

 quiry commenced to inquire there were but 

 two worms described as being in the alimentary 

 canal of the grouse the large tape-worm which 

 lives in the small intestine all the year round, 

 known to every sportsman, and a slender thread- 

 worm which inhabits the paired caeca, or blind- 

 guts, which are unusually large in the grouse 

 and play a very important part in its digestion. 

 The latter worm under certain conditions, and 

 when present in considerable numbers, is associ- 

 ated with one of the two diseases which have 

 especially attracted the attention of the Inquiry. 



Davainea urogalli (Modeer). Of the three tape- 

 worms that are found in the grouse, this species 

 is by far the largest and by far the most common. 

 It exhibits little seasonal variation, and is found 

 in considerable numbers all the year round. 

 The birds become infected at an early age. 



D. urogalli is normally found in the small 

 intestine, though sometimes parts of it are found 



