50 BULLETIN: MUSEU:\I OF COMPARATIVE ZOOLOGY. 



here introduced, has resulted in my determining that a distinct oral aper- 

 ture is developed upon one side of the body at a short distance only 

 from the apical extremity. This orifice takes the form of a transvei'se 

 slit, and is followed by a narrow oesophageal tract which opens into the 

 capacious digestive cavity that occupies one half or two thirds of the 

 posterior region of the body. The plan recommended by Dr. Leidy for 

 observing the vital phenomena of these animalcules is to empty out the 

 intestine of the White Ant containing them into a little white of egg. I 

 also have found this material favorable for their observation, but have 

 gained an additional insight into their life histor}' by emji^ying in a 

 like manner thinly diluted milk. In this medium they not only live for 

 a considerable time, but meet with abundant nutriment, their pharynx 

 and digestive cavity being frequently found densely packed with its 

 component corpuscles after their immersion in this fluid for a short 

 interval." 



Unfortunately, Kent does not give any figures, and I have been un- 

 able to discover in the living animals the mouth he describes. However, 

 the existence of such a structure covild, I imagined, be easily determined 

 by means of sections. These I endeavored to procure by sectioning the 

 whole alimentary canal of the Tennes, hoping in this way to obtain some 

 sections of Trichonympha in a direction favorable for settling this point. 

 I was not disappointed. 



To my astonishment I found that the small intestine was completely 

 packed with animalcules, and among them hundreds of Trichonympha ; 

 these, however, were not promiscuously distributed through the parasitic 

 mass, but were, as a rule, excluded from the periphei'y of the intestine. 

 This position, of course, precluded the possibility of their attaching 

 themselves directly to the wall of the host's intestine. 



The sections of Trichonympha thus obtained revealed absolutely no 

 trace of such an oral aperture as that described by Kent. They did 

 show, however, an interesting condition of affairs, which I think may 

 perhaps account for the presence of the numerous fragments of ligneous 

 fibre and other food particles so often found within the body, without 

 necessarily supposing them to have entered through a persistent mouth. 

 In many of the cross sections of the posterior half of Trichonympha I 

 observed deep folds of the body wall ; these almost invariably contained 

 cilia, doubtless engulfed at the time of the folding (Plate 2, Figs. 9, 10, 

 and 14). Particles of wood fibre were also seen entangled among the 

 cilia in these folds (Fig. 10, fbr. lig.). I think we have in this condition 

 an explanation of the mystery. Cilia entangling particles of woody fibre 



