004 UK. II. 1!. lANTIIAM ON TIM': [May.*?, 



development of the various blood-eell.s of birds — on wliicli our 

 }ii-esent knowledge is nie.agre an<l contradictory — running parallel 

 with the researches on infected birds, stuilying the young stages 

 of the Leucocytozoiin. 



The host-cell of L. lovati soon becomes di-awn out at the emls, 

 that is. the cell becomes spindle-.shapHd. This is probably due to 

 a deformity of the cells bu)iiglit al)out by the movements of the 

 piirasite within. Wenyon (11)08) considers that some spindle- 

 siiaped cells occur normally in the blood of birds and reptiles. I 

 have very rarely seen spindle shapeil cells in the blood of grou.se, 

 though 1 have found spindle-shaped cells to be more numerous 

 in the blood of fowl-chicks {cf. Fantham, P. Z. S. 19 10, PI. LXIII. 

 lig. 18) dying from coccidiosis. Howevei", 1 would not suggest, 

 on present evidence, that coccidiosis is either directly or indirectly 

 responsible for the appearance of spindle-cells in the blood. 



The presence of Leucocytozoa does not always cau.se the body 

 of the host-cell to become spindle-shaped. Mathis and Leger 

 (190il) found that the host-cell of Leiicoci/iozodn caidleryi of the 

 Tonkin fowl did not have its ends drawn out. They also con- 

 sidered that the host-cell was probably a mononuclear leucocyte. 



Per.sonally, I have seen the spindle or horn-like end of the host- 

 cell of L. lovati elongate during the movements of the ]iarasite 

 within it. Further, both ends usually are elongate (PI. LX. 

 ligs. 19-22), in other cases one end only becomes deformed 

 (tig. 18), while in a very few cases the cell contour has been 

 largely unaffected by the parasite (tig. 17). When both ends 

 of the host-cell are affected, it not infrequently happens that 

 the elongation of one end is greater than that of the other 

 (PI. LIX. figs. 4-6). The shape of the ho.st-cell of different 

 Leucocytozoa may be merely a reflex of the motility of the 

 jiarasite within. It is not wise, therefore, to lay too great stress 

 at present on the spindle shape of the hi^st-cvUs in diagnosing the 

 Leucocytozoa of birds. 



(c) MorpJidhxiji of the PiO-asiie. 

 ) (It'll// Ftiytiis. 

 TUe parasite in its younger stages is vermiform and like a 

 ha-mogregarine (PI. LIX. tigs. 1-3; PI. LX. figs. 17-22) and is 

 moi-c refractile in life than the host-cell containing it. Young 

 forms are by no means common, a. feature Z. lovati shares with 

 L. c(Oulleri/i where they have rarely been seen, The nucleus of 

 the host-cell is displaced to one side (PI. LIX. figs. If)) and the 

 Jiarasite moves very .slowly within the cell, slight wave-like move- 

 ments or pulsations jia.ssing fiom the middle of the parasite 

 towai'ds either end. 1'he parasite grows in length and breadth 

 meanwhile (figs. 4-8), and the ends of the ho.st-cell become 

 gradually more and more drawn out (tigs. 4-9, 18-22). As 

 mcntiontMl al)ovi\ .Mimetimes one end of the containing cell is 

 more drawn out than the other (tigs. 4 (i). Fiee \( rmicules of 

 L. Ifirati ha\c \-t'ry rarely been .seen in my preparations. 



