14 
INTRODUCTION. 
IV. 
cult of observation. At length, among the highest Algae we encounter what appear 
to be really tAvo sexes, one analogous to the anther and the other to the pistil of 
flowering plants. It Avould seem, however, that it is not each individual spore 
which is fertilized, as is the case in seed-bearing plants ; but that the fertilizing 
influence is imparted to the pistil or sporangium itself, when that body is in its 
most elementary form, long before any spore is produced in its substance, and even 
when it is itself scarcely to be distinguished from an ordinary cell. Anther idia, as 
the supposed fertilizing organs are called, are most readily seen among the Fucacece , 
and will be described under that family. 
Besides the reproduction by means of proper spores, many Algte have a second 
mode of continuing the species, and some even a third. Among the simpler kinds, 
Avliere the Avhole body consists of a single cell, a fissiparous division, exactly similar 
to the fissiparous multiplication of cells among higher plants, takes place. This cell, 
as has been already mentioned, divides at maturity into two parts, Avhich, falling 
asunder, become separate individuals. Similar self-division has been noticed among 
the lower Palmellacece , and in other imperfectly organized families. Such a mode 
of multiplying individuals is analogous to the propagation of larger plants by the 
process of gemmation, where buds are formed and thrown off to become new indivi- 
duals. When, as in the Lemna or Duckweed , the whole vegetable body is as simple 
as a phanerogamous plant can Avell be, the ucav frondlets or buds are produced in 
a manner very strikingly analogous to the production of new fronds in Desmidiacece. 
The third mode of continuing the species has been observed in many Algae of the 
green series, in some of which sporangia are also formed, but in others no fructifica- 
tion other than what I am about to describe has been detected. This mode is as 
follows. In an early stage, the green matter, or endochrome , contained Avithin the cells 
of these Algae, is of a nearly homogeneous consistence throughout, and semi-fluid ; 
but at an advanced period it becomes more and more granulated. The granules 
when formed in the cells at first adhere to the inner surface of the membranous 
wall, but soon detach themselves and float freely in the cell. At first they are 
of irregular shapes, but they gradually become spheroidal. They then congregate 
into a dense mass in the centre of the cell, and a movement aptly compared to that 
of the swarming of bees round their queen begins to take place. One by one 
these active granules detach themselves from the swarm, and move about 
in the vacant space of the cell Avith great vivacity. Continually pushing against 
the sides of the cell Avail, they at length pierce it, and issue from their prison into 
the surrounding fluid, Avliere their seemingly spontaneous movements are continued 
for some time. These vivacious granules, or zoospores as they have been called, at 
length become fixed to some submerged object, where they soon begin to develop 
cells, and at length grow into Algae similar to those from whose cells they issued. 
Their spontaneous movements before and immediately subsequent to emission 
lead me to speak of the 
MOVEMENTS OF ALGiE 
in general. These are of various kinds, and of greater or less degrees of vivacity 
