8 



PROTOZOANS. 



Order I. Flagellata (Monads]. 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, that vibrates 

 and whirls about as 

 the animal moves 

 along. One of the 

 Monads, the Noctihi- 

 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 

 FIG. 6. Giant monad Noctiluca. e, gastric issues a single whip, 

 vacuole ; Radiating filaments. or c ilium, 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. 



NOTE. 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 



