THE GENERA OF MOSSES. 
451 
calculate that the total number of teeth is thirty-two: 
but it is very difficult, if not impossible, to say where the 
separations are to commence, or how many are actually to 
take place. This is remarkably illustrated in ^S*. sphwri^ 
cum, in which the line down each geminated tooth, or the 
Unea separahilis, appears as strong as that by which actual 
separation is produced. This structure sufficiently accounts 
for the different combinations observable in the teeth of the 
peristome, not only in the different species, but even in the 
same species. As fev/, or indeed any, plates exist which 
give a correct representation of the peristomes of the 
Splachna, and as most descriptions are equally erroneous 
(or at least only partially correct), we subjoin the result of 
our own extended observations. 
1. S. ampullaceum. In this species the teeth are, in some 
specimens, 16 unigeminated, and geminating in 
pairs : in others (and more usually) 8, equidistant, 
bigeminated. 
% S. vasculosum presents the same variation. Hedwig's 
figure of both species is incorrect. That of the pre« 
sent one, extremely so, except in the leaves. 
3. sphcBricum, This varies more than any other in 
the combinations of the teeth. There are in gene- 
ral 8, equidistant, either entire or slit down to the 
middle, and each of the divisions marked with a 
semipellucid line. Sometimes there are only 4, equi- 
distant, each made up of 8 parts. In other speci- 
mens, again, there are 16 teeth, in the dry state, 
geminating in pairs, each with a longitudinal semi- 
pellucid line. 
4. S. Wornishioldii. Peristome more regular; consist- 
ing, according to Brown's observations and our 
own, of 16 equidistant unigeminated teeth. The 
r f 2 
