20 BOTANICAL GAZETTE [JULY 
They vary greatly in size, but are commonly longer than broad, 
ranging in length from 258 to 332m and in width from 258 to 
3064. The antherozoids of Ginkgo, as described by Hirase,* are 
egg-shaped and 82m long by 49 wide. Compared with these, 
the antherozoids of Zamia are surprisingly large, being plainly 
visible to the unaided eye. In Cycas, according to Ikeno, they 
are somewhat larger than in Ginkgo. I judge from this that they 
are also much larger in Zamia than in Cycas. The numerous 
cilia which are developed from the spirally arranged band, as 
described above, give the pointed end of the antherozoid a striking 
helicoid appearance. There is no free tail in Zamia, as is said by 
Hirase to occur in Ginkgo. The nucleus is very large (fig. 22), 
occupying a large portion of the body, and is surrounded on all 
sides by a thin layer of cytoplasm (fg. 2 cp). The vibrations 
of the cilia in vigorous antherozoids are exceedingly rapid and 
difficult to study. Judging from observations made on certain 
antherozoids just starting motion and others which had nearly 
exhausted their energy, there would seem to be a rhythmic con- 
traction of the cilia which passes quickly from one end of the 
band to the other. A tremulous vibration of the cilia, appar- 
ently independent of the rhythmic contraction, can be observed 
in the weaker motion of extreme youth and age. Whether this 
occurs in the period of vigorous rapid motion could not be 
determined. The motion of the antherozoid is comparatively 
slow and sluggish. In pollen tubes placed in sugar solution the 
two antherozoids frequently move around very vigorously, bump- 
ing against each other and the wall of the pollen tube. They 
seldom escape from the upper cut end of the pollen tube, 
although they as frequently swim toward this end of the tube as 
the other end, so far as could be observed. In a number of 
instances the pollen tubes were cut so that the antherozoids 
escaped and their unobstructed motion was thus observed. The 
Flautschicht of the antherozoid is very tender, however, and is 
commonly broken in attempting to remove the latter from the 
4 Hrrase, Dr. S.—Untersuchungen iiber das Verhalten des Pollens von Ginkgo 
biloba. Bot. Centralb. 69:34. 14 Ja. 1897. 
LG — 4 =a 
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