OF ANIMALCULES. 57 



tion of which are small globular cavities, in which 

 the food is digested. This apparatus, and indica- 

 tions of ovary clusters, probably attached to the main 

 trunk, are all that has been discovered of its internal 

 organization. All the figures are magnified in the same 

 proportion, and the real length of a mature specimen 

 (Figure 38) is 1- 140th of an inch. 



These creatures prey on other animalcules nearly as 

 large as themselves, which they devour entire ; this will 

 account for the variety of forms which they assume, and 

 require an observer to be very watchful and cautious, 

 before he can pronounce on the identity of a species. 

 Dr. Ehrenberg, by patient observation, saw one indi- 

 vidual undergo a great variety of forms, when it had 

 swallowed a young KoJpoda cucuUus. To explain this 

 effect, figure 36 shews a young specimen with open 

 mouth, about to devour the animalcule at figure 39 : 

 this it accomplishes by the motion of the fringe of ciliae 

 producing a current in the water : the prey by this means 

 is brought in contact with the mouth-aperture, which 

 gradually dilates till the animalcule is entirely enclosed. 

 During this operation it swims about, and a casual ob- 

 server would readily imagine the form shewn at figure 40 

 as the normal shape of an animalcule, while, in fact, it is 

 occasioned by its food. As the digestion proceeds, the 

 lower part dilates, and the anterior contracts into its 

 former shape; the animalcule then assumes an egg-shape, 

 and finally returns to its true form. 



