Reports to the Board of Agriculture. 175 
We do not know the life-history of any of the three definite 
Grouse Cestodes. 
Mr. Munro Ferguson should be informed that it is not at all 
necessary to kill off all his rabbits because of grouse disease, as there 
is no connection between Avian and Rabbit tapeworms, which was 
thought to be the case owing to curious Davainea-Wko, cysticercoid 
forms being found in rabbits. 
In all cases where the life-history of Avian tapeworms have been 
traced out, the intermediate host has proved to be a slug ( Limctx ), 
snail {Helix), insect or earthworm for land birds, water insects, or 
Crustacea for ducks and other water fowl. Probably the Grouse 
Cestodes have a similar life-history. The -same applies to sheep ; 
there can be no connecting the Moniezias of sheep and the Davainea, 
etc., of birds. 
The Nematode parasites of grouse should be investigated both in 
diseased and healthy birds. As an example of the different effect of 
these two groups of parasites upon their host, the rabbit may be 
mentioned. This rodent is frequently heavily infested with tape- 
worms, and yet lives on apparently unharmed ; now and then cases 
of great mortality amongst rabbits have been investigated, and the 
cause readily traced to Strongylidse (vide Report Journ. S. E. Agri. 
Coll., no. 8, p. 60, etc.). 
Dr. Cobbold believed grouse disease to be due, anyhow, in part to 
a small intestinal Strongyle, but this matter does not seem to have 
been definitely worked out. 
On certain moors there are undoubtedly epidemics of tapeworm 
which, by virtue of their numbers, do kill off the young birds. 
Probably there are several factors which are the cause of grouse 
disease — entozoa, bacteria, degenerated stock. 
•The disease or diseases are encouraged by (1) destruction of 
animals and birds of prey, and (2) overstocking. 
