49 
pressed, it liberated immense numbers of spores, which 
were in great part aggregated into globular or oblong 
clusters, the larger being as much as ‘02 mm. (20”) in 
diameter. The spores themselves were short and thick, 
with bluntly-rounded ends, their length beimg about 
0025 mm. (24), and a little less in breadth. Here also 
there is little doubt that we have to deal with a Crypto- 
eyst (Microsporidian), but in the absence of figures it is 
rather uncertain in what genus this parasite should be 
placed. From the mention of distinct clusters or clumps 
of spores, and the shape of these latter, I am somewhat 
inclined to regard this case as one of infection by 
Pleistophora, rather than by Glugea—the reason will be 
referred to below. 
My own acquaintance with these parasites began in 
the summer of 1901, when Mr. Todd, then Assistant to the 
Director of the Plymouth Marine Biological Laboratory, 
brought to my notice the intestine of a plaice which, 
although, unlike Johnstone’s specimen, it was quite 
healthy in appearance, presented certain abnormal 
features. 
The gut had been fixed in Corrosive and Acetic, and 
preserved in spirit, and shewed at intervals little oval 
patches, usually projecting shghtiy, on the outer coelomic 
side. Besides these, there were little out-growths of the 
tissue of the wall, often in the form of pear-shaped appen- 
dages, attached by the narrow end to the gut. These 
patches and projections indicated the site of the infection, 
and were readily to be distinguished by their rather 
different colour, having a faint reddish tinge added to 
the pale nondescript shade of the preserved gut. I 
gathered from Mr. Todd that, when fresh, the spots were 
of the usual Sporozoan opaque-white. A point worth 
noting in the position of the parasites is that they were 
D 
