OF MICRO-ORGANISMS. 47 



Concerning the prehension of foods and the search 

 for nutriment on the part of Ciliates, we can do no better 

 than to quote entire a note which M. E. Maupas has 

 been pleased to send us upon the subject. We had 

 put to him two questions: First, do the Ciliates hunt 

 their food? Second, while in quest of live prey, do the 

 Ciliates called hunters make an actual hunt, involving 

 the espial of prey from a distance and the voluntary 

 pursuit of the same in the circuitous paths they fol- 

 low? M. E. Maupas after having once more had re- 

 course to observation, bciefly recapitulates his opinion 

 in the following lines: 



"From the standpoint of prehension of food, the 

 Ciliates may be divided into two great groups: 



1. Ciliates with alimentary vortices; 



2. Hunter Ciliates. 



"In the first group the mouth is always held wide 

 open, and along with the nutritive particles which the 

 current of the vortex keeps constantly sucking in, we 

 may at will cause other, absolutely inert and indigesti- 

 ble, particles to take the same course; for instance, 

 such substances as granules of carmine, indigo, and 

 rice-starch. These granules, totally unfit for nutritive 

 purposes, pass through the body of the Ciliates along 

 with the genuine nutriment and are finally cast out 

 intact with the excrement. I think, therefore, we 

 may affirm that the species having alimentary vortices 

 exercise no real choice in selecting their foods, and 

 that they absorb indiscriminately all corpuscules which 

 by reason of fheir form and density admit of being 

 seized and drawn into the alimentary whirlpool. 



" In the case of the hunter Ciliates proper, the 

 mouth is constantly closed. The act of absorbing each 

 object captured is accomplished by a process of de- 



