520 Reproduction in Fresh- Water Algae.  [September, 
which a part of the contents is escaping, while in the other branch 
an oval body is seen. These represent the asexual spores, a more 
enlarged example of which is seen at c, and are nothing more than 
‘portions of the green protoplasmic contents of the filaments which 
contract and escape through the rupture at the tip. These spores 
are covered with a number of cilia, by the movement of which 
they are able to move about quite rapidly for a short time ; then, 
coming to rest, they germinate, and produce a new Vaucheria. 
When a sexual spore is produced the process is somewhat differ- 
ent. At certain points on the filament, not far distant from each — 
other, two projections arise: the one grows more slender than 
the other (d) and becomes much twisted upon itself. This is the 
male organ, called antheridium, and in it are produced the anther- 
ozoids, small bodies (e) provided with two cilia for movement; 
they resemble the zodspores of the Cladophora, though having a 
quite different office to perform. The other projection is the 
(Fia. 92.) VOLVOX. 
female organ, odgoniwm, and is usually of an ovoid shape and 
filled with granular matter. When the time for fertilization 
comes, the wall of this organ is ruptured at the end nearest the 
antheridium, from which there passes out at the same time a mass 
of antherozoids, some of which find their way to the contents of 
the odgonium and fertilize it. Soon a new growth takes place m 
this newly fertilized body, and a double cell-wall is formed over 
it, the whole becoming a well-protected, resting spore 5 it ad 
provided with no cilia and therefore has no movement of its 
own 
Is it not easy to trace the similarity between the sexual repro 
duction of Vaucheria and that of flowering plants? 
The Volvocinex comprise a peculiar group of plants, the mem- 
