ent from the loose structure of that
of a schizont. The male elements (microgametes) are formed in a manner
essentially comparable to that in which the formation of merozoites
takes place. Although the details of the nuclear changes and divisions
vary somewhat, the end-result is similar, a number of little nuclear
agglomerations being evenly distributed at the surface (VII. [mars])
Each of these elongates considerably, becoming comma-shaped and
projecting from the gametocyte. Nearly all the body of the male gamete
(VIII. [mars]) consists of chromatin, the cytoplasm only forming a very
delicate zone or envelope around the nucleus. From the cytoplasm two
long fine flagella grow out, one of which originates at the anterior
end, the other, apparently, at the hinder end, acting as a rudder; but
it is probable that this also is developed at the anterior end and
attached to the side of the body. By means of their flagella the
numerous microgametes break loose from the body of the microgametocyte
and swim away in search of a female element.

A megagametocyte (VI. [venus]) is distinguished by its rather different
shape, being more like a bean than a sphere until ripe for maturation,
and by the fact that it stores up in its cytoplasm quantities of reserve
nutriment in the form of rounded refringent plastinoid grains. Each
female gametocyte gives rise to only a single female element
(megagamete), after a process of nuclear purification. The karyosome is
expelled from the nucleus into the cytoplasm, where it breaks up at once
into fragments (VII. [venus]). Meanwhile the gametocyte is becoming
spherical, and its changes in shape aid in setting it free from the
shrivelled host-cell. The fragments of the karyosome, which are, as it
were, squeezed out to the exterior, exert a powerful attraction upon the
microgametes, many of which swarm round the now mature megagamete. The
female nucleus (pronucleus) approaches the surface of the cell (VIII.
[venus]), and at this spot a little clear cytoplasmic prominence arises
(cone of reception). On coming into contact with this protuberance
(probably attracted to it by the female pronucleus), a microgamete
adheres. Partly by its own movements and partly by the withdrawal of the
cone of attraction, the male penetrates into the female element and
fertilization is accomplished. Only one microgamete can thus pass into
the megagamete, for immediately its entry is effected a delicate
membrane is secrete