722 DR. H. B. FAXTHAM ON [^lilV 3, 



EXPLANATION OF PLATE LXIL 



All figures outlined with Abbe oaniova Incida, using Zeiss 2 mm. 

 apocliromatie lens. 



Figs. 1, 2, 3 from stained (hannatoxylin) sections of gut of grouse chick infected with 



coccidiosis. X loOO apijnixiinately. 

 Figs. 4-14 from fresh preparations. X lOOU. 



Figs. 1, 2. Section of gut showing parasites. 

 par. — \mriiB\te. 



s^«. = sporozoite (infecting germ). 

 »«2. = merozoite (davighter form). 

 (J =micr<)iiamet('s (male elements) attached to microgametocyte 



((? mother cell). 

 $ =macn)ii-amete (female), with thin cyst around it. 



3. Fertilisation of large macrogamete by minute microgamete. Only one male 



element penetrates, thi> others remain on the outside and degenerate. 



4, 5. Oocysts, characteristic of fresh fa>ces. 



6, 7. Oiicysts with four developing sporoblasts inside, fii-st round, then ovoid. 



8. Mature oocyst containing four sporocysts, each with two spoi'ozoites, from 



c;ccal drojjpings taken from tlie nioDvs. 



9, 10. Free sporocysts (spores) from infected ficccs. In the sporocyst reiirc- 



sented in fig. 10, which is pointed at one end, the sporozoites are about 

 to emerge. 



11. Round cyst, as found in droppings of grouse or fowl chicks. 



12. Somewhat egg-slia])ed cyst, with four sporoblasts (young spores). 



13. Cyst of Coccidium (Eiitiei-ia) pfcifferi (Labbe) Irom a pigeon infected 



with natural coccidiosis. 



14. Cyst from fa;ces of a pigeon fe(l on infected grouse fa'ces. 



4. Observations on tlie BlootI of Grouse. By H. B. 

 Fantham, D.Sc.Lond., B.A.Oantab., A.R.O.s"., F.Z.S., 

 Christ's Colleoe, Cambridge, Assistant to the Quick 

 Professor of Biology in the University, Protozoologist 

 to the Grouse Disease Inquiry. 



[Received April 5, 1910.] 



(Plate LXIII.*) 



1. IXTiiODUCTION. 



Tlie elements of tli(! hlood of birds are very different from 

 those of mammid.s, and while innch is known of the histology 

 of mammalian blood, the investigation of the blood of birds has 

 hitherto been veiy limited, and very little indeed is known of 

 the subject. Such literature as i.s available on avian blood is, 

 unfortunately, largely contradictory, and the few illustrations 

 relating to the same have not solved entirely the diliiculties 

 connected with the cellular elements of the blood of birds. 



The portions of the subject that have been most adequately 

 dealt with are tho.se relating to certain pathological conditions, 

 fowl cholera and fowl typhoid, occurring in domestic fowls, and 

 those relating to normal fowls' blood. In connection with both 



* For e.\i)lanatioii of the Plate see p. 731. 



