94 DESCRIPTION OP [Polygastrica. 



17. MONAS punctum. The point egg -shaped Monad. 

 Revolves on the longitudinal axis of its body. (See 

 engraving, group 2 ; the lower figure exhibits one under- 

 going longitudinal division.) Found in water with tannin. 

 Size 1-1 150th. 



B. ELONGATED MONADS. 

 (#). True Elongated Monads. 



18. MONAS cylindrica. The cylinder- shaped Monad. 

 Solitary, colourless, revolves as it progresses. Found in 

 salt water. Size 1-1 150th. 



19. MONAS Okenii. Okens elongated Monad. Red, 

 revolving, vibratory motion, social. Found in running 

 water. Size l-2300th. 



(b). Conical. 



20. MONAS deses. The lazy Monad. Green, solitary. 

 Found in water from hills. Size 1 -1200th. 



21. MONAS socialis. The social Monad. Colourless, 

 social. Found in water-butts. Size 1 -700th. 



(c). Top-shaped. 



22. MONAS flavicans. The yellow Monad. Social, 

 gliding motion. Found in ditch-water. Size 1-1 720th. 



(c?). Spindle-shaped (*), colourless. 



23. MONAS simplex. The simple spindle Monad. 

 Gliding and rotatory motion. Found in water of the Nile, 

 and at Berlin. Size 1-1 720th. 



24. MONAS inanis. The empty spindle Monad. 

 Vacillating motion. Found in stagnant and foul water. 

 Size l-3600th. 



25. MONAS scintillans. The sparkling spindle Monad. 

 Very active. Vacillating motion. Found amongst fresh 

 water conferva, &c. Size 1- 6000th to l-4600th. 



