126 
The N.Z. Journal of Science and Technology. [June 
NOTES ON MALARIAL INFECTION IN THE IMPORTED 
SKYLARK. 
By A. B. Dore. 
The yearly examination of blood-films from birds obtained in the Waikato 
district has shown the occurrence of malarial parasites in the imported 
thrush and blackbird and in the native ground-lark. This year 140 birds, 
comprising thirteen species, were examined for haematozoa, and malarial 
parasites were observed in another species of imported bird. This species 
was repeatedly examined for evidence of malarial infection for the past 
seven years, with negative results until this year. 
Plasmodium of the Imported Skylark ( Alauda arvensis). 
The infected birds were shot at Kimihia, in the Waikato district, on 
the 17th January, 1921. Blood-films were prepared direct from the heart, 
fixed in absolute alcohol, and stained 
by the Giemsa method. Examination 
of the most heavily infected bird 
showed that 15 per cent, of its erythro¬ 
cytes harboured plasmodia, whilst in 
others the number of parasites en¬ 
countered on a slide did not exceed 
ten. The majority of infected erythro¬ 
cytes were partly dehaemoglobinized. 
Occasionally a disintegrated erythro¬ 
cyte was observed, and a collection 
of twelve to sixteen merozoites were 
usually scattered around the nucleus 
of the host cell. All stages of schizo¬ 
gony were observed in the blood from 
one bird, from merozoites recently 
invading a cell to mature male and 
female gametocytes. The nuclei of 
the parasites stained well, and were 
fairly uniform in size. Melanin, un¬ 
evenly distributed, was' present in all 
parasites, with the exception of forms 
measuring less than 3*2 /x. 
Nuclear displacement of host cells 
was marked. Multiple infection was 
present in several erythrocytes, and the greatest number of young forms 
encountered in a cell was four. Measurements of adult plasmodia averaged 
7-6 /x by 5-4 /x. 
A count of 400 consecutive parasites showed the following percentages : 
Male gametocytes, 60 per cent. ; female gametocytes, 35 per cent. ; doubt¬ 
ful forms, 5 per cent. Five per cent, of the skylarks examined were infected 
with this parasite. 
A 
&<*<» 
0 £ 9 Q 
Fig. 1 . —Plasmodium of the skylark. 
A, merozoites lying adjacent to 
nucleus of host cell; B and C, plas- 
modia in ruptured erythrocytes, 
from which nuclei have been ex¬ 
truded ; D, merosoite formation; 
E, free male gametocyte. 
