56 NATURAL HISTORY 



It is very inactive and slothful. Found among duck- 

 weed. Length, 1 -1200th of an inch. 



Ehrenberg has placed it in a new genus (for the cha- 

 racters of which, see Book III.) He has also given the 

 following species : — 



63. Bacterium cj/didric. — 1-1 100th of an inch. 



54. — . enchelis. Thejlask Bacterium, al. sp. 



—1-2880 of an inch. 



65. Bacterivm fuscum, al. sp.—U 1500th of an inch. 



GQ. — . monas. — I-4000th of an inch. 



67. punctum. — l-4000th of an inch. 



Qg. , fermo.— l-6000th of an inch. 



(39. . tremulans, — 1- 3400th of an inch. 



70. Enchelis pw;;?a et farcimen. — The puppet Jiask 

 Animalcule, and the E. farcimen are given by MuUer as 

 distinct species, but in fact they are the same at dif- 

 ferent stages of its growth ; the forms it assumes are 

 influenced by the prey it feeds on. Figures 36 and 37, 

 which represent young ones, are the latter, and figure 

 38 the former species of that naturalist. 



This animalcule is furnished with a fringe of ciliae 

 around the mouth, as shewn in figures 36, 37, and 38 ; 

 by means of this it can occasion currents in the water, 

 as indicated by the arrows in figure 38. Its digestive 

 function is not performed by a simple alimentary canal ; 

 but in the apparatus shewn at figure 41, a large di- 

 gestive trunk, traversing the body from one extremity 

 to the other, slightly enlarged near the end, and 

 sending out branches in all directions, at the termina- 



