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liable to vary. The gills are the part com* 
monly known by that name, and with which 
every one is acquainted; they affume different 
colours in different fpecies, and vary much 
in their refpeclive lengths ; each gill confifts 
of two membranes, and between thefe the 
feeds are formed ; the gills are always at- 
. tached to the hat, and fometimes to that only; 
fometimes they are not only fixed to the 
ftem, but extended along it downwards, like 
the wires of an umbrella. This has been 
called a decnrrent gill. Mr. Curtis difcovered 
•a peculiarity of ftruc~ture in the gills of the 
vagaricus ovatus, which he had not before ob- 
served in any other fungus: the gills are con- 
nected together by numerous tranfverfe bars, 
or filaments/ the ufe of which feems to be to 
keep them at an equal diftance from each 
.other, and thus to admit the air to the fructi- 
fications, which are fituated on the flat fur- 
face of the folds, and to prevent their being 
-deftroyed by preffure from their too great 
..clofenefs. Thefe bars make it extremely dim> 
■ cult to feparate one of thefe folds entire: 
"they are vifible only when greatly magnified. 
The fecondary fubdivifions of the agarics are 
founded upon the folidity or hollownefs 
of 
