OF THE MOSSES AND THEIR ALLIES. 
149 
The vagimile, which answers to a certain extent to the 
calyx of the Phanerogamia, at first encloses the spore-case ; 
the latter, however, soon bursts through its cellular en- 
velope, and is elevated on a delicate threadlike stem. The 
vaginule should be examined in its early state, previous to 
its losing its contents, first from the exterior ; and, when its 
outward form is familiar to the observer, he should divide 
it under water into two halves longitudinally, in one of 
which he will see the organs of fructification in a greater 
or less degree of development. Ordinarily this division of 
the vaginule may be easily effected by means of a forceps 
in each hand ; occasionally it is of so fleshy a nature as to 
allow of being cut with a knife. 
For studying the anatomical structure of the fruit of the 
Mosses a capsule must be taken with the fruit not yet ripe. 
Thin sections, vertical and horizontal, may be made with 
great ease. A peculiar organ is found in the capsules of 
nearly all the Hepaticse, called the elater. It is a single or 
double filament, spirally twisted, and enveloped in a slender 
tube : both tube and elater form interesting objects for the 
microscope. Of what service the elaters may be in the 
economy of the plant is not yet accurately ascertained ; 
their probable office is to disperse the spores by their elas- 
tic movement as soon as the latter are ripe. 
A still more mysterious organ found in the antheridia of 
most of the Mosses is the spermatozoid, or antherozoid, 
or spermatic filament ; for by all these names it is known 
among botanists. It is a minute thread, of ■which the 
functions are not yet known. On being placed in water 
these spermatozoids exhibit active spontaneous motion, as 
may be seen by squeezing the contents of a ripe antheridium 
into a drop of water on a slide, covering it with thin glass, 
and then submitting it to a microscope with a power of 
from 300 to 600 diameters. If the movements are too 
quick for observation, they may be retarded by allowing a 
drop of iodide solution to make its way under the covering 
glass. * 
