xv, 4 Be Leon: Balantidium Haughwouti 405 



occurring free in fresh waters in Connecticut, in the United 

 States, but he says nothing regarding the possible source of the 

 parasites. Haughwout(5) has briefly discussed the matter of a 

 free-living stage in the life cycle of Trichomonas and raised a 

 question as to the identity of the organisms described by several 

 authors as occurring free. 



METHOD OF FEEDING 



These animals are very voracious, continuing to feed, under 

 the cover glass, almost up to the time of death. When feeding 

 they move slowly and evenly forward, producing, by means of 

 the adoral membranelles, a powerful current of water near the 

 anterior end. This current simulates a whirlpool, the vertex of 

 which points toward the oral depression. It is produced by the 

 coordinated succession of rapid lashing movements of the mem- 

 branelles and cilia from without oral ward. This movement pro- 

 duces to the eye the effect of a rotating peristome or the trochal 

 disk of a rotifer. The current of water impinges on the oral 

 vestibule at an effective angle at one side. There is a sideflow 

 which leaves the depression on the opposite side much as is seen 

 in the case of VorticeUa. There apparently is little, if any, 

 choice of food at the intaking — every object below a certain size 

 is swept into the pharynx; the rest goes out in the sideflow. 

 Such selection as there is must be rapid, judging from the rapid- 

 ity of the inward and outward flow of water from the oral cavity. 

 It would seem that selection is governed more by the size of 

 particles taken into the oral opening than by the quality. 



THE RELATION BETWEEN THE MEGANUCLEUS AND THE 



MICRONUCLEUS 



This relation presents one of the most interesting features for 

 future work with this species. It is unfortunate that out of 

 many hundreds of individuals studied not one has been seen in 

 division, and no conjugating pairs have been found. 



TJie enclosure of the micronucleus within the meganucleus is 

 too regular in its occurrence to be accidental, or without signif- 

 icance of some kind. Two possibilities suggest themselves: 

 Either it represents a type of nuclear division of a rather new 

 and remarkable kind, or it represents a process of nuclear re- 

 organization perhaps along the line of endomixis. Unfortu- 

 nately the picture so far presented is too incomplete to admit 

 of definite conclusions regarding either supposition. There is 

 also the added handicap of incomplete knowledge of division 

 phases of the micronucleus. 



