Pythium de Baryanum . 657 
remain straight or have a characteristic curvature (Figs. 7, 13). 
In the intercalary oogonium, two stalk-antheridia may develop* 
one on either side of the oogonium. 
The branch-antheridilim is the one more commonly found. 
It is a terminal cell of a special branch of the hyphae, arising 
usually as a lateral branch of the hypha supporting the oogo- 
nium, and very often quite near the latter (Figs. 4, 8, ii). 
But sometimes* though rarely, it develops from a separate 
hypha near the oogonium. The antheridial branch grows 
towards the oogonium, and its rounded end finally comes 
in contact with the wall of the latter (Figs. 7-1 1). A septum 
is now formed in the branch, cutting off ah elongated curved 
cell, the antheridium. More than one antheridium may be 
found in connexion with a single oogonium, frequently two 
antheridia (Fig. 10) and sometimes three. 
A young oogonium, which is about 20 to 25 /u in diameter, 
contains approximately from ten to fifteen nuclei. The nuclei 
are more or less spherical, being larger than those of the 
hyphae. The chromatin granules are more prominent, and no 
nucleoli are found. It is very difficult to count the number 
of nuclei in the antheridium, . owing to its small size and 
irregular shape. The number seems to vary from two to six. 
The division of the nuclei takes place almost simultaneously 
in the oogonium and antheridium (Figs. 13-17). In the 
oogonium, the nuclei, before division, arrange themselves near 
the periphery. The division of the nucleus is karyokinetic 
and is very similar to that which takes place in Cystopus and 
Peronospora as described by Wager (’ 96 , ’00), Stevens (’ 99 ), 
Davis (’00) and others. The several karyokinetic figures are 
shown in Fig. 25 . 
The chromatin granules first of all appear to be transformed 
into a number of chromosomes in the shape of very short 
rods or oval bodies. By the formation of the spindle they 
arrange themselves in the equatorial plate (Fig. 25 a). The 
number of chromosomes is very difficult to count, but 
in several cases I was able to count as many as eight. 
The nuclear membrane seems to remain intact, at least in 
