OF THE MOSSES AND THEIR ALLIES. 149 



The vaginule, wiich answers to a certain extent to the 

 calyx of the Phanerogarnia, 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 Hepaticge, 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. 



