lO 
MORPHOLOGY OF THE CELL, 
cell conjugates with two others, and takes up both their protoplasm-masses ; in these 
cases the zygospore is the product, of three cells. In the Myxomycetes the swarm-cells 
(Myxo-amoebae), which are endowed with a peculiar motion, coalesce gradually in great 
numbers, and finally form large, motile, naked protoplasm-masses, the Plasmodia, which 
only at a subsequent period are transformed into a number of cells. 
In the cases hitherto considered the uniting protoplasm-masses are of equal size ; 
the process of fertilisation in many Cryptogams differs from them only in the fact 
that the two protoplasm-masses which coalesce are of unequal size, and otherwise 
of different properties. In Book II. we shall treat in detail of the reproduction of 
Cryptogams ; here we need only state that the male fertilising bodies (antherozoids) 
of Cryptogams are usually motile naked protoplasm-masses, that is, primordial cells; the 
female organ of these plants usually opens outwardly, and contains a primordial cell 
Fig. ^.—Spirogyra longata. Cells of two filaments in an early stage of conjugation, showing the spirally coiled chlorophyll-bands, 
in the chlorophyll-granules of which lie rings of starch-grains ; small drops of oil are also distributed through them (see Sect. 6) This 
is the condition of the chiorophyll after the action of strong sunlight ; the nuclei are also to be seen in the cells, each surrounded by 
protoplasm, threads of which reach the cell-wall in different places ; a and b are the protuberances in two different stages (X 550). 
(oosphere) which is fertilised by the antherozoids. In cases which have been accurately 
observed [CEdogonium, Faucheria) these coalesce with the former, and the new cell 
results from this coalescence. As with the Conjugatse and some Fungi, the cell formed 
in this manner is always a reproductive cell ; with it begins the growth of a new 
individual plant. 
3. Free Cell-formation. — In the protoplasm of a cell new centres of formation 
arise, round each of which a portion of the protoplasm collects, and forms a cell. 
A portion of the protoplasm may remain and represent the protoplasm-mass of 
the mother-cell which persists for a longer or shorter time. [The new centres of 
formation are indicated by the previous appearance of nuclei formed by the repeated 
