1897 | DEVELOPMENT OF THE ANTHEROZOIDS OF ZAMIA 17 
tion of the spindle formed in the division of the generative cell, 
and median sections in this stage show the deeply stained sec- 
tions of the band lying on opposite sides of the cell (jig. 76). 
The band gradually elongates and finally forms five or six turns - 
around the cell, which are arranged in a 
helicoid spiral on the surface, usually about 
opposite the side of the cell attached to 
the other antherozoid (fig. 2). Viewed 
from the apex of the spiral the turns, 
beginning at the apex, run in the direc- 
tion opposite to that of the hands of a 
clock. No exceptions to this rule have 
been observed. In an early stage of its 
development very numerous protuberances 
can be discovered on the outer surface of 
the band. These gradually increase in 
length and become plainly visible by the tive cell, showing, 
time the band has formed one turn around TSS section, the spiral 
the cell (fig. 1). They continue to grow a eaten 
: oped one turn: #, nu 
in length and ultimately form the motile cleus; ¢, cytoplasm; 4, 
cilia of the mature antherozoids (figs. 2 and spiral band. cca 
3). The band varies considerably in width at various stages, 
becoming continually narrower as its 
development proceeds. In a mature 
\., Stage, just before the antherozoids 
escape from the pollen tube, it is usu- 
ally from 5 to 8“ wide. During the 
development of the spiral cilia-bearing 
band the cell becomes changed consid- 
erably in shape and appearance, as 
shown by comparing jig. 2 with jig. 7. 
The band which, as explained above, 
Fic. 1. Young an- 
therozoid formed by the 
division of the genera- 
in 
Fic. 2. Cross section of nearl 
i y ie 4 
Mature antherozoid: m, nucleus ; finally mops 0c, Sie Ss ee cogs 
<P, cytoplasm; 4, spiralband; with the Mautschicht of the cell, is 
200, 
¢, cilia, x apparently invariably developed on 
the side of the cell opposite to the partition wall formed in 
