D. L. MACKINNON 
35 
1910, towards the close of my investigation; the spores were ripe, and 
the infection so intense that I could not fail to notice it. 
The parasitised larva moves about sluggishly, and has a swollen, 
congested appearance. On opening the body I was at once struck by 
the curious, chalk-white colour of the fat-body. Examination showed 
that the whole tissue was replaced by the masses of spores of some 
microsporidian. These were all at an advanced stage of development: 
the majority shovved four spores within each pansporoblast, but in 
many cases the outlines of the pansporoblast were lost, and the spores 
set free. 
Figs. 13—14 (PI. Ill) illustrate the parasite as I found it. The 
pansporoblasts are oval to round in form, and measure from 8 ya x 5 /u- to 
11 yu, X 6 ya. The pear-shaped spores (4—5 ya x 2'5—3 ya) are arranged 
therein in two superimposed rows : sometimes the narrow ends all 
point the same way (Text-fig. 6), more often the narrow ends of the 
upper row lie above the broad ends of the row beneath (Text-figs. 7 and 
8). The large pansporoblasts occasionally hold only three spores, and 
Fig. 6. Fig. 7. Fig. 8. 
Text-figs. 6, 7 and 8. Drawings of the living pansporoblasts of Gurleya legeri, 
to show the arrangements of the spores. 
these seem bigger than where there are the usual number. These 
spores would correspond to Hesse’s macrospores, but I do not find the 
difference in size between the macrospores and microspores so great as 
he describes it in the parasite from Ephemerella. If sulphuric acid be 
brought in contact with the spores, the filament is shot out to a 
length of nearly 25 p. 
Systematic position. The genus Gurleya, Dofiein, is distinguished 
from other microsporidia of the Oligosporea by the possession of 
tetrasporous pansporoblasts. At present the genus contains three 
species: 
Gurleya tetraspora, Dofiein (1898), 
G. legem, Hesse (1903), 
and G. francottei, Leger and Duboscq (1909). 
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