12 



ZOOLOGY. 



Fig.7. — Gregarina from 

 the alimentary canal 

 ofabeetle. ^young- 

 er state, with a beak 



In swimming, the monad stretches out the whip-lash-like 

 appendage called the fiagellum, which vibrates with an un- 

 dulating, whirling motion, and produces 

 a peculiar graceful rolling motion of 

 the monad. When the monad is fixed 

 the flagellnm is used to convey food to the 

 mouth, which lies between the base of 

 the fiagellum and beak, or "lip." The 

 food is thrown by a sudden jerk, and with 

 precision, directly against the mouth. 

 "If acceptable for food, the fiagellum 

 presses its base down upon the morsel, 

 and at the same time the lip is thrown 

 back so as to disclose the mouth, and 

 then bent over the particle as it sinks 

 into the latter. When the lip has ob- 

 tained a fair hold upon the food, the 



^ co ?k n ^°?i£] fiagellum withdraws from its incumbent 



of the head. 2, older; o 



a, anterior end; 6, position and returns to its former rigid, 



hinder part of the * » 



body; c nucleus, watchful condition. Ihe process of de- 



Highly magnified. . . x 



glutition is then carried on by the help 

 of the lip alone, which expands latterly until it completely 

 overlies the particle. All this is done quite rap- 

 idly, in a few seconds, and then the food glides 

 quickly into the depths of the body, and is envel- 

 oped in a digestive vacuole, whilst the lip assumes 

 its usual conical shape and proportions." (Clark.) 

 Some monads are attached by a slender stalk to 

 veiia, a the leaves and stems of aquatic plants, and these 



flagellate 1 -, j 



infuson- are usually collected into compound monads, sev- 

 eral arising from a common stalk. In such cases 

 the body with its nucleus and two or three con- 

 tractile vesicles is surmounted by a delicate collar, 

 out of which the lash (fiagellum) projects. 

 Monads multiply (1) either by self-division, or (2) 

 by the production of great numbers of extremely minute 

 germs. Hence the minutest of all beings reproduce frou 



an, or 

 monad, 

 with two 

 large ci- 

 lia called 

 flagella. 

 Greatly 

 magni- 

 fied. 



