OF MICRO-ORGANISMS. 51 



speak, and partly enclosing them in its pliable body, 

 already seemed suspicious. At last, it made a direct 

 attack upon one of them by fastening itself upon the 

 upper part of its body. It opened its huge mouth, 

 which is never to be seen except when the animal is 

 eating, and slipped over the Epistylis like the finger 

 of a glove being drawn upon a finger of the hand. 

 We saw the sides of the buccal aperture (which are 

 capable of being dilated in a truly astonishing man- 

 ner) slip slowly over the peristome and upon the body 

 of its prey, and then draw together about the point 

 where it was made fast to the pedicle. The cilia cov- 

 ering the body of the Amphileptus began to shake with 

 that peculiar motion which is always noticed when a 

 ciliated Infusory secretes a cyst. At the expiration of 

 a moment or so, a fine line was seen to appear around 

 the whole body which continued to spread so as 

 soon to form the cyst." (This might be called a cyst 

 of digestion.) "The phenomenon as a whole is quite 

 simple. An Amphileptiis approaches an Epistylis 

 devours it and encysts itself upon the spot, the 

 victim being still attached to its pedicle. It then en- 

 deavors to wrench the Epistylis from its point of at- 

 tachment by twisting; it turns on its axis from left to 

 right and then from right to left, successively; when 

 it has succeeded, it continues its work of digestion, 

 and occasionally divides in two within the cyst itself. 

 During the last stage of digestion, it rests for a while, 

 when it commences again to turn about in the cyst, 

 evidently seeking to disengage itself. At the close of 

 a certain number of hours, the cyst breaks. The 

 Amphileptus issues forth and starts in quest of another 

 victim."* 



^Etudes sur les Iri/usoires et les Rhizopodes^ Vol. II. p. l66, l86i. 



