THE GENERA OF MOSSiES. 
ISl 
mium nudum. Columella prima sstate, magna, ampla, sed 
una cum membrana opercular!, postea ita deprimitur, ut, 
membranam thecse maturse fundum obtegentem simulet, et 
nulla dicatur. Sporulce vel pauco-angulatse, superficiebus 
convexis, imperforatis ; vel subsph^ricse reticulatse. 
Char. Diff. Tlieca Integra in receptaculum sessilis. 
Fruct. The receptacle is in the form of a lens, or, in 
other words, is dilated horizontally into a much flattened 
oblate spheroid ; of a brownish-white colour, and apparent- 
ly pedunculated, the peduncle being somewhat paler, vary- 
ing in length from half an inch to an inch and a half, or 
more, and of consideiable thickness, — rather liable to be 
twisted when dry, and probably a continuation of the caulis 
or stem. The calyptra is of a pale colour, " like a white veil,'"* 
remarkably tender, at an early period entirely inclosing the 
theca, and bound to its base at its conjunction with the recep- 
tacle, but soon tearing transversely and irregularly through 
the middle. Its lower part, or vaginula, still continues to ad- 
here to its place of attachment ; but the upper portion, or 
true calyptra, is very fugacious. Neither seta nor apophysis 
can be said to be present, the receptacle forming the im- 
mediate support to the theca. The theca is entire, ovate, 
globose, urceolate or turbinate ; and all these modifications 
frequently occur in the same species : it is generally wi- 
dened at the mouth, of a rusty-brown, with its surface de- 
stitute of either striae or sulci. The operculum is somewhat 
plane, or inclining to convex, and similar in colour to the 
theca, from which it is at an early period detached. The 
peristomium is naked. The columella in the young theca 
is of no small dimensions, but, by the drying up of the pulp 
which it contains, sinks along with its opercular membrane 
so low, as to present the appearance of a mere horizontal 
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