OF ANIMALCULES. 135 



shell, and terminating a little below the middle : in the 

 centre of this, Dr. E. has observed the small aperture of 

 the throat. They have sometimes appeared to me to re- 

 ceive the food at the upper end, which in some indivi- 

 duals is indented. I have never succeeded in feeding it 

 with indigo, but finely divided carmine it swallows 

 freely, and the digestive sacs may be observed to fill in 

 succession. It also devours the Monas punctum, which 

 is attached by a filament to decomposed vegetables ; this it 

 accomplishes by a sudden spring at the Monad, instantly 

 retreating as soon as it is caught. When it swims it is 

 very nimble, and difllicult to examine : it sometimes 

 creeps, employing the lateral and end bristles for feet, as 

 shewn at figure 186. It propagates both by longitudinal 

 and transverse division : the latter is shewn at figure 185 : 

 it would also appear to be produced from spawn ; (see 

 the young one, figure 183.) Found in various vegetable 

 infusions. Size, l-280th of an inch. Magnifying power 

 fromSOO to 500. 



309. Trichoda cunex. — This animalcule is covered 

 with a crustaceous shield, and resembles the last, ex- 

 cepting that no longitudinal furrows are ever observed on 

 its back ; it is furnished with a cluster of strong bristles 

 at each extremity ; these it employs as feet when it walks. 



310. Trichoda cicada, — Oval, with a dark margin, 

 and the anterior furnished with fine cilia in addition 

 to the bristles, as in the preceding species, from which it 

 does not differ essentially. 



