20 
FERNS AND FERNERIES . 
These antheridia consist of stalked cellular bodies of 
simple but peculiar structure, in the interior of which are 
developed minute cellules (small cells), sometimes called 
sperm-cells (fig. 11, 2, h } i). When the antheridia are 
ripe, the sperm-cells escape, each of the cells containing 
ciliated spiral filaments called spermatozoids (fig. n, 
h, i). Some time after the yet immature antheridia 
are produced, other reproductive organs called arche- 
gonia , or ovule-like bodies, are formed in the centre 
of the prothallus (fig. n, 4). These are the female 
organs, which gradually form four cells, in tiers, with 
a central canal leading to an embryo-sac, in which 
lies a germinal body, something like, but smaller than, 
the ovules of higher plants (fig. 11, e). This body in 
course of time becomes fertilized by the entrance of the 
spermatozoids which are liberated from the sperm-cells 
of the antheridia (fig. 11, i). The embryo-cell having 
thus become fertile develops into a true embryo, and 
forms leaves and rootlets (fig. 1 i,f g), which grow and 
mature until a minute fern is developed, precisely the 
same in form and structure as the parent plant. Ferns 
also produce bud-like bodies called gemmce on the leaves 
