Sexual Organs of Phytophthora ery thro septic a, Pethyb. 133 
convoluted. The point where separate chromosomes arise was not seen. 
When they appear they are small oval or even round bodies, much less in 
combined volume than the spireme, but still larger than they become later 
(Figs. 39 and 41). The nucleolus has also begun to diminish in size, and this 
diminution is continued further during metaphase. The chromosomes are 
most easily counted now or a little later when they go to the equatorial plate. 
The number is small and may be stated with considerable certainty to lie 
between four and six. The formation of the spindle and the marshalling 
of the chromosomes on the plate have not been followed (Figs. 42 and 43). 
The activity in this respect of the centrosomes, which, without asters, are 
afterwards seen at the tips of the spindle, remain problematical. Curved 
spindles are frequently seen, but whether they represent young stages or 
not is not always clear. 
Once formed the spindle is normally straight and entirely intranuclear 
(Figs. 42 to 45). At the same time it may remain curved because it is some¬ 
times seen to be of that shape during anaphase. The nucleolus is still present, 
but it is now reduced to about the size of a chromosome. It may lie in any 
part of the nucleus, near the plate or by one of the poles. The chromo¬ 
somes are regularly arranged at the equatorial plate, and they too are now 
smaller in size and spherical or slightly oval in shape. The spindle is 
stout at first, but a little later it seems to lengthen out somewhat, the 
nucleus becoming elongated at the same time (cf. Figs. 42 and 46). 
Anaphase is now setting in, and the chromosomes begin to travel to the 
poles one by one—at least they do not go all at once (Figs. 46 and 47). 
The nucleolus is lost to view and its further fate is unknown. At the same 
time the nuclear membrane disappears. Telophase is a prominent feature 
(Fig. 49). The two groups of chromosomes and the spindle between them 
make up a body of an obtusely oval shape. There is no membrane 
surrounding it, but the remains of the fibres are still seen stretching across 
the space between. The daughter nuclei finally result. 
The stages following telophase are the most difficult of all to follow, 
and little can be said about them. The reason for this is that all the 
nuclei begin to degenerate almost at once, with the exception of one in the 
centre of each oogonium (Figs. 20, 22, and 23). Of course this holds for at 
least one nucleus in the antheridium also, but it is even more difficult to 
follow events there. This places one point a ! t least beyond all doubt—that 
there is only one division of all the surviving nuclei in both organs. The 
functional female nucleus appears quite normal (Figs, 22 and 23); it is very 
small and contains a small nucleolus and a small amount of chromatin. 
The peripheral nuclei occasionally appear normal also, but they never, 
in our experience, stain as sharply as the central one. They must begin to 
break down very soon afterwards, for they are practically always seen in 
a condition of evident disintegration. This process does not follow quite 
