HABITS AND REACTIONS OF LACRYMARIA 235 



well filled with them. These plants in their life processes use 

 waste products formed by the animals in which they live and in 

 turn form substances of which the animals make use as food, 

 that is they are symbiotic. They are not merely temporarily 

 located in the animals, but live in them generation after gene- 

 ration. This is shown by the following facts: 



(i) A number of Lacrymaria were isolated and examined from 

 time to time for several days. In these and in numerous other 

 specimens examined at different times but not isolated all of 

 the algae found were at all times bright green, indicating that 

 they were alive and not undergoing digestion. (2) No similar 

 algae were found free in the solution. (3) The algae found in 

 Lacrymaria are identical, both in size and structure, with those 

 found in Paramecium bursaria, an organism in which they are 

 known to be symbiotic. 



These algae are nearly spherical in form, contain three or 

 four relatively large chloroplasts and have a diameter about one- 

 seventh the width of Lacrymaria. How the algae get into and 

 become fixed in theSe creatures I am unable to say, but it is 

 likely that they are symbiotic in unicellular forms which are 

 taken in as food. At any rate, these ciliates in all probability 

 feed on organisms which sometimes contain algae. 



Only four specimens of Lacrymaria were seen in the act of 

 feeding, and in only two cases was it certain that the food was 

 actually alive, although it probably was in all. The process of 

 seizing an object and engulfing it is so rapid that it is very diffi- 

 cult to be certain as to its nature. In two of the four cases ob- 

 served the object swallowed was probably an ameba. In the 

 third it was a small globular ciliate, apparently Halteria ; and in 

 the fourth it was a flagellate, probably Chilomonas. In one 

 instance the substance swallowed had a volume fully equal to 

 that of Lacrymaria. This mass was engulfed with surprising 

 rapidity, but it passed slowly down the neck which was dis- 

 tended to a size fully equal to or a little larger than that of the 

 body. The mass finally lodged in the anterior end of the body 

 nearly doubling its length. The ciliate was engulfed in less than 

 a second, but it required fully fifteen seconds to pass dow^n 

 through the neck which was bulged out much like the neck of 

 an ostrich in swallowing an orange. The diameter of the ciliate 

 was nearly three-fourths the width of the body of the lacry- 



