8 PROTOZOANS. 
Order I. Flagellata (J@onads).—If standing water is 
examined with a microscope, it will be found fairly alive 
with numbers of minute pear- and oval-shaped creatures, 
having, at the place 
where the stem would 
be, alash, thatvibrates 
and whirls about as 
the animal moves 
along. One of the 
Monads, the /Voctilu- 
ca (Fig. 6), a giant of 
its kind, lives in the 
ocean, and in appear- 
ance resembles a cur- 
rant about the size 
of a small pin-head. 
On one side there is 
a groove, from which 
Fic. 6,—Giant monad Woctiluca. ¢, gastric issues a single whip, 
vacuole ; g, radiating filaments. or cilium, that is a lo- 
comotive organ, and 
near where this joins the body is the mouth. The outer 
surface of the animal is a firm membrane, beneath which 
is the jelly-like mass containing numerous granules, from 
which rises a regular network of fibers that lead over the 
entire body. The young are produced by a mere break- 
ing off of a portion of the parent. 
Nore.—As many as thirty thousand of these forms have been seen 
in the ocean in a cubic inch, moving about with great rapidity, and 
producing a most wonderful phosphorescent light. 
Other monads are compound (several joined together), 
as the Uvella, while others are fixed, attached to the bottom 
by a slender stalk, as the Codosiga, Here the little hair- 
like organ is used to throw food into the mouth. Others 
of this order have their delicate forms protected by a hard 
