SPOROZOON PARASITES OF QUEENSLAND FRESHWATER FISH. 521 
is slit open, numerous round filmy pieces of matter float out 
with the bile. These are the plasmodia. They are ofa 
pale yellowish to green colour, and vary in diameter from 
3to12mm, The small forms are young plasmodia and 
contain no mature spores, while the largest have abundance 
of them. In life the protoplasm can be distinguished into 
a clear narrow ectoplasm, about ten micra in width and a 
coarsely grained endoplasm. When placed in bile, diluted 
with normal saline, the plasmodia do not seem capable of 
actually changing their position, but undulations may be 
seen to travel round the margin of the organism. The 
plasmodium is very delicate and easily injured. In some 
cases the bile was swarming with myriads of ripe spores, 
in other cases of less advanced infection they were much 
less numerous. 
The spore is spindle shaped and sharply pointed at both 
extremities. The polar capsules are more or less rounded 
structures lying one at either end of the spore. There are 
two medianly situated nuclei. Faint longitudinal striations 
are visible. .The average dimensions are:—length of spore 
9—10+, breadth 44; length of polar capsule 2—3y, breadth 
L—2p. 
Auerbach’ has recorded 11 described species of Myxidium 
from fish. Theyare most commonly found in the gall bladder. 
MYXOSOMA OGILBYI 0. sp. 
Figs. 2, 17. 
Host:—The golden perch, Plectroplites ambiguus 
Richardson. 
In three out of nine specimens examined tiny white cysts 
were observed in the white fibrous tissue of the gill arch, 
usually close to the bases of the filaments. The cysts were 
quite small, being on the average less than a millimetre in 
* Auerbach, ‘‘ Die Cnidcsporidien,” pp. 170-8, 1910. 
