Aug. ix, 1923 
Phytophthora Faberi on Coconut and Cacao 
279 
soon as a zoospore finds the opening it comes to rest and gradually oozes 
out, becoming much elongated in the process and constricted in the 
middle and bulging out at both ends, due to the smallness of the opening 
(PL 11, A and B). After the zoospore passes through, it comes to rest 
for a portion of a second and then swims off actively. While one zoospore 
is passing out, the rest within swim about against the wall until the open¬ 
ing is again free, when one by one they will escape in the same manner. 
The zoospores are granular, slightly greenish, and have distinct nuclei 
and one or two vacuoles. From a side view they are kidney shaped, and 
when observed from the end a groove is seen on one side from tip to tip. 
The swarm spores swim about for a time by means of two flagella. Just 
Fig. 3.—Arrangement in classes of the ratios of the length to the width of conidia (coconut), showing the 
limits of variation. 
before coming to a permanent rest the spores become sluggish, settle 
down for a time, then start off, settle down again, and swim away once 
more, and finally settle down again definitely. No distinct spore wall 
was noted on the motile spores, but as soon as they came to a permanent 
rest a wall could be distinguished, which was especially clear when germi¬ 
nation started (PI. 11, A and B). In the rest stage the spores became 
spherical, in some cases with a depression on one side, took on a more 
greenish tinge, became more granular, enlarged somewhat, and then put 
out germ tubes which grew into a mycelium (PI. 11, A and B). In 25 
minutes the germ tube of one zoospore on potato dextrose agar was 
observed to double in length. Frequently in hanging drop slides of water 
and dilute agar all the zoospores were produced from secondary sporangia 
that arose from the original spores placed in the drop or on the agar. 
54484—23 - 3 
