CHAPTER VII 



THE ANIMALS WHICH LIVE ON OR WITHIN THE GROUSE 



IT is necessary to begin this short account of the animals which 

 live on or in Grouse by apologising for the length of many of 

 the words employed and in some cases for their technical 

 nature. It has not been found possible wholly to do without 

 them, but in most cases the scientific names of the various 

 animals mentioned are given in footnotes, and an attempt 

 has been made to explain the technical terms used. 



Like other animals, the Grouse supports a number of parasites 

 living on or in it which we can collectively call its " fauna." 

 On the outside of its skin, amongst the base of the feathers, 

 numerous insects browse, whilst beneath the skin in the spaces 

 of the body, such as that of the alimentary canal, and in the 

 cells and tissues, such as the epithelium or lining membrane 

 of the intestine and in the blood, worms and unicellular 

 animals (Protozoa) swarm. During the last four years these 

 parasites have all been investigated, some more, others less, 

 closely, according as they seem to throw much or little light 

 on the health and disease of the bird. In the account which 

 follows the members of the Grouse's fauna are numbered 

 consecutively so as to give some idea of its wealth and 

 variety. 



The animals which live beneath the skin and within the 

 body of the Grouse constitute the " Endoparasites " of the 

 Grouse, whilst the animals that live on the outside of the skin 

 are termed the "Ectoparasites." Amongst the last-named is 

 included the Grouse - fly. 1 This fly is said to suck the 



1 Ornilhvmi/ia lagopodis, Sharp. 

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