220 The Significance of Sex. {March 
segmentation like sperm mother-cells before being set free. The mother from which 
they budded is the macrogonidium, and is itself soon fertilized by a microgonidium, 
which is the child of another macrogonidium, c shows the first step in this conjuga- 
tion. The nucleus, both in the macro- and the. micro-individual, segments up into 
bits, oe and smaller, and the microgonidium being absorbed, its microsomata 
are added to the more numerous microsomata of the female. Then there is gradua 
fusion al the single nucleus i is reconstituted. Before this happens there may be 
division and budding, as in @ and 4. An exactly similar series of phenomena is 
described for Zpzsty/is ania 
Fic. 128, a-e. Conjugation of ahem pete Brit., “ Protozoa.””—This illus- 
trates “temporary conjugation.” æ is a normal individual; å, two united for sexual 
ends. The nucleus and paranucleus divide successively, the former into eS the 
—_— a kow _ and bce they fuse Do ay parey oaiae in e; REDE 
pa icle eus, 
functions of the nucleus. The individuals separate and couse asexual tere 
This is probably an incomplete account of what happens. There is much co! 
about this ill-understood process, but we must assume that there is nee airc 
of microsomata between the two individuals in harmony with some observations, and 
thus bring this process into line with what we know happens in ai other cases of fer- 
tilization. (See text for further discussion.) 
IG. 129. Fertilization of egg of Bat—Van Beneden and Julin, A. B., i.— 
two pronuclei are seen each in a vesicle lying in a clear space in the vitellus and in 
proximity to each other. 
Fic. 130, a—g. Fertilization of ovum sad ee eer 
A. m. A., xx.—In @ we see a large fi ronucleus 
in the egg. In ġ each has been crowned by an aster. The male pronucleus now 
moves towards and fuses with the female pronucleus (c). The chromatin of the 
male pronucleus may split as in d, but soon all the chromatin of the fertilized nucleus 
is transformed into a segmented “skein” (e). At the same time polar asters appear, 
whose rays drive the segments to the equator (/), where they arrange themselves 
a regular plate, split, and pass to the poles, there constituting the daughter-nuclei, 
one of which is shown at g, still crowned by its aster. 
Fic. 131, a-b. “ Genetic blending” of Dallingeria drysdali—J. R. M. S., April, 
1886.—We may suppose the form with one flagellum, large nucleus, and granular 
zone to be female ; then the form with three flagella and small nucleus is mal i 
nuclei and bodies fuse to one individual, and then the nucleus is dissolved, and the 
cell is encysted, finally to burst, as myriads of spores, scarce visible under fifteen 
thousand diameters magnificati 
Fic. 132, a-d. Fertilization r S in Orchis latifolia—Strasburger, Befruch- _ 
so ea animale ore , Jena, 1884; see also Jen. Zeits., xi—Two | 
sorts of nuclei, “ germinative’” and “ vepar are found in the pollen-grain and 
and these may multiply by karyokinesis. The former alone act as male pro- l 
sitll, eek Whee thet more than one, the first one to make a egg 
