12 
rise to eggs one season and to male cells another year. When 
a drop of the milky fluid from a ripe male is mixed with a 
little sea water and examined with a magnifying power of 
•one hundred diameters, it is seen at a glance to he quite dif- 
ferent from the fluid of a female. There are no large bodies 
like the eggs, but the fluid is filled with innumerable num- 
bers of minute granules (Figure 48), which are so small 
that they are barely visible when magnified one hundred 
diameters. They are not uniformly distributed, but are 
much more numerous at some points than at others, and for 
this reason the fluid has a cloudy or curdled appearance. By 
selecting a place where the granules are few and pretty well 
scattered, very careful watching will show that each of them 
has a lively dancing motion, and examination with a power 
of five hundred diameters will show that each of them is tad- 
poll-shaped (Figure 50), and consists of a small, oval, sharply 
defined “ head ” and a long, delicate “ tail,” by the lashing 
of which the dancing is produced. 
It is more difficult to decide whether the male cells are per- 
fectly ripe than it is to decide in the case of the eggs. With 
a magnifying power of five hundred diameters, each “ head ” 
should have a clear, well-marked outline, and they should be 
very uniform in size, and separated from each other, as in 
Figure 50. Under very favorable circumstances this power 
should also show the “ tails,” as very faint undulating lines. 
If the “ heads ” vary much in size, or if they are aggre- 
gated into bunches, with the “ tails” radiating from the 
bunches in all directions, or if there is much granular matter 
so small that the outlines of the particles are not visible 
when magnified five hundred diameters, the fluid is not per- 
fectly ripe, aud fertilization with it will not in all probability 
be very successful. 
NUMBER OF EGGS. 
As the male cells are infinitely more numerous than the 
eggs, the ripe fluid from even one small male is enough to 
fertilize all the eggs of five or six large females. 
