Enchdia.] THE INFUSORIA. 279 



Dr. Ehrenberg has figured, in his large work, the form of 

 the nutritive system separately. Common in stagnant 

 bog water. Length l-140th. 



430. ENCHELYS fardmen (E. fardmen et Vibrio 

 intestinum, M.) The sausage-shaped Enchelys is smaller, 

 more cylindrical and slender than the preceding species; 

 the ova are whitish. 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 observa- 

 tion, saw one individual undergo a great variety of forms 

 when it had swallowed a young Kolpoda cucullus. To 

 explain this effect, fig. 260 shews a young specimen with 

 open mouth, about to devour an animalcule; this it ac- 

 complishes by the motion of the fringe of cilii producing 

 a current in the water; the prey by this means is brought 

 into contact with the mouth aperture, which gradually 

 dilates till the animalcule is entirely inclosed. During 

 this operation it swims about, and a casual observer would 

 imagine the form shewn at^'g. 26 1 as the normal shape of 

 another 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 (figures^ 262 to 265), and 

 finally returns to its true form. Found in stagnant water. 

 Length l-430th. 



431. ENCHELYS infuscata. The brown-mouthed Enchelys 

 has an oval or spherical whitish body; the mouth encircled 

 by a brownish ring, and not prominent. When fed with 



