236 THE GROUSE IN HEALTH AND IN DISEASE 



detail in the celebrated memoir of the late Dr Schaudinn (1900) on Eimeria 

 {Coccidium) schubergi, parasitic in the gut of the centipede Lithohius forjicatus. 



Coccidia have been recorded from most of the gi-eat groups of the metazoa, but 

 very few coccidian life-histories have been investigated completely. 



Dr Leiper, while working on helminthiasis in Grouse in May 1909, noticed the 

 occurrence of coccidian cysts in large numbers in the gut of many Grouse chicks, 

 with concomitant enteritis, very often proving fatal. The coccidian cysts are oval, 

 and at first sight might easily be mistaken for eggs of worms. Dr Leiper suggested 

 that Coccidiosis was a factor in " Grouse Disease," especially in young birds. Early 

 in June 1909 I spent some time on one of Lord Lovat's moors in Scotland for the 

 purpose of investigating Coccidiosis in Grouse chicks.' Previously we had noticed, 

 at various times, the occurrence of Coccidian cysts in adult Grouse, but not in large 

 numbers. I have much pleasure in expressing my thanks to Lord Lovat, Dr A. E. 

 Shipley, Dr E. A. Wilson, Dr Hammond Smith, and Dr Leiper for aiding my 

 researches by procuring material for me, and to Professor Nuttall, in whose 

 laboratory much of my work was done. I also availed myself of the services of 

 the Secretary of the Committee, who placed me in communication with a large 

 body of correspondents through whom I obtained further material to enable me 

 to continue the investigation, and to whom my thanks are tendered. 



In this paper I wish to record my researches on tlie morphology and life-history 

 of Eimeria avium, more especially as it occurs in the Grouse. I would point out 

 that the length of time at my disposal for these researches has been limited, only 

 one season being available to me for procuring material, and I have had several 

 other investigations to consider during the period, so that I was not able to give 

 undivided attention to the elucidation of the protozoa of Grouse. However, the 

 complete life-cycle of Eimeria avium, responsible for the dwindling of Grouse 

 broods in spring, is here set forth for the first time, so far as I am aware. 



II. The Generic Names Eimeria A^^) Coccidium. 



Unfortunately, owing to the rule of priority, the generic name Coccidium 

 (Leuckart, 1879) no longer holds, but is replaced by that oi Eimeria (A. Schneider, 

 1875). I am in sympathy with Professor Minchin, when he writes in a recent 

 review : — " We regret to see the familiar generic name Coccidium replaced by 

 Eimeria ; this is one of those many cases where, in our opinion, rebellion against 



' The number of Grouse chicks dying of Coccidiosis on the moors is not easily estimated, for the chicks die 

 in the lieather, and their tiny corpses are rarely found. 



