342 THE GROUSE IN HEALTH AND IN DISEASE 



embryos lie in small packets which do not seem to be in a uterus, and may be, as 

 Morell suggests in D. urogalli, in the lumen of the ovary itself. 



This tapeworm, common in chickens and turkeys, is only an occasional 

 parasite of the Grouse, and has in many hundreds of birds we have examined only 

 been found twice, and in neither case has its presence been associated with any 

 lesions. As a factor in " Grouse Disease " it may be neglected. In both cases only 

 young, immature, not fully-grown specimens were met with. Its second host is 

 according to Railliet, quoting Grassi and Rovelli, probably some Coleopteran or 

 Lepidopteran ; but at present this has not been proved. 



HYMENOLEPIS Weinland, 1858. 

 (iii.) HYMENOLEPIS MICROPS (Diesing), 1850. 

 Synonyms: Tcenia microps (Diesing), 1850. 



Hymenolepis tetraonis (Wolffh.), 1900. 1 



This is an extremely delicate transparent tapeworm which exists in almost 

 countless numbers in the duodenum of Lagopus scoticus. It is also recorded from 

 the Blackcock and the Capercaillie. On cutting open the duodenum of a Grouse 

 infested with these worms and we have rarely found a bird free from them except 

 in the winter months they are not at first apparent. They are so fine, and so 

 transparent that they are practically invisible when alive, and the contents of this 

 part of the alimentary canal appears very much like a thick pure'e. If we add to 

 this some fixing agent such as corrosive sublimate this puree resolves itself into a 

 mass of very fine, delicate, white threads inextricably tangled up together, and so 

 numerous that there seems but little room left in the duodenum for the passage 

 of the food (PL LIL). If, with great care for they break at the slightest 

 strain we succeed in disentangling one of those worms we shall find its head 

 embedded to a greater or less extent in the mucous lining of the duodenum, into 

 which, to use a poetic phrase, " it nuzzles," whilst the body of the worm floats 

 freely in the fluid contents of this part of the alimentary canal. If we also succeed 

 in freeing the head we now have a complete worm, and can study its structure. 



Before giving some of anatomical details of H. microps it is worth mentioning 

 that Wolffhiigel found fragments of this species none with the head in the 

 small intestine, large intestine, and end he does not say which end of the caeca 

 of Tetrao urogallus. We have also found short chains of ripe proglottides passing 



1 K. Wolffhiigel, "Beitragzur Kenntniss der Vogelhelmintlien," Inaug-Diss., Freiburg-i-B., 1900. 



