SPOROZOON PARASITES OF QUEENSLAND FRESHWATER FISH. 527 
position in the connective tissue covering the ovary, but as 
growth proceeded, the cyst had come to press down among 
the developing ova, though it was still surrounded by a 
hypertrophied layer of this tissue. 
The spore is a tiny pyriform structure with a mass of 
more deeply staining material at the narrower end. The 
average length is 3—5y, while the breadth is 2—3y. Its 
morphological characteristics and the formation of an 
indefinite number of spores relegate this organism to the 
genus Pleistophora. 
Host. PARASITE, 
Nematalosa elongata Henneguya sp. 
Plectroplites ambiguus Myxosoma ogilbyz J. and B, 
Myzxobolus plectroplites J. and B. 
Henneguya australis J, and B. 
Sciena australis Pleistophora sciene J. and B. 
Therapon carbo Myxidium therapon J. and B. 
Therapon hallo Myxidium therapon J. and B. 
Henneguya gracilis J. and B. 
All figures (1 — 9) on Plates XLIII and XLIV have been drawn 
to the same magnification, (see scale beside fig. 1). The photo- 
micrographs have not been retouched in any way. References to 
lettering :—c, cyst; ¢.t., connective tissue surrounding cyst; d.s., 
developing spores; ect., ectoplasm; end., endoplasm; g.t., gill tissue; 
k.t., kidney tissue; ov., ovum; s., spores; s.f., skeleton of gill 
filament. | 
EXPLANATION OF PLATES. 
Puate XLII. 
. Group of spores of Myxidium therapon. x 1250. 
. Myxosoma ogilbyi. x 1250. 
. Myxobolus plectroplites. x 1250. 
. Henneguya australis. x 1250. 
33 “ abnormal spores. x 1250. 
a gracilis, %* 1250. 
oF WOH 
a 
