118 
NEW AllHANGEMEN r OF 
which (L. erecium of Brown), Dr Hooker figures and 
describes the nienibraiiaceoiis peristomiuni as bearing traces 
of imperfect teeth *. 
The gradual sphtting, in Calymipere.s^ of the membrane 
into the teeth, which are never erect, is admirably calculated 
to render the dispersion of the sporules more perfect. ; 
We suspect that the lining to the theca, the columella, 
and perhaps also its terminating membrane, will never be 
found wanting in any moss, if it be examined at the period 
most favourable to their development, which must neces- 
sarily take place at different ages in different species, but 
especially in different genera. There are, however, some 
instances in which the reverse has been maintained. An- 
drtea has been denied a lining to the theca ■[-. Phascum 
serratum, and some others, are generally declared to have no 
columella, while there is an evident one in Ph. rectum and 
Ph. curvicollum. In regard to Andraa, we believe that the 
hning is present before the theca bursts into its four valves ; 
an operation extremely liable to render a delicate membrane 
evanescent. With regard to the Phasca, the minuteness 
of the theca in a young state is such, as to render the dis- 
section very difficult : we therefore confess, that we have 
not by actual observation been able to establish our opinions 
in this instance; but have httle doubt, however, that a 
columella is truly present ; and we conceive that, at an early 
period, the membrane, which connects it to the lining of the 
theca, gives way, thus allowing it to shrink to the base of 
the theca, and from its minuteness to become inconspicuous. 
The whole genus Sphagnum has more than once deceived 
us by the apparent total absence of this part, and it was 
not until we had repeatedly examined the theca, before it 
* Muse. Exot, Tab. 169. -j- HooKKa in Linn. Trans, voi. x. 
