of the Tasmam'an White Ant. 451 



of the hair-like cilia which clothe the entire surface of the 

 body. In the last-named species a portion of these cilia are 

 as long as or longer than the body, and exhibit under certain 

 conditions a remarkable plume-like aspect. In the Tasmanian 

 species, which, by way of compliment to the talented dis- 

 coverer of the genus, I propose to distinguish by the title of 

 Trichonympha Leidyi, the length of the cilia but little exceeds 

 that of many of the Opalinidse and other previously known 

 endoparasitic Infusoria. It is furthermore not so easy to 

 recognize in the present species that the cilia, with respect to 

 their length, form three or four more or less distinct series, as 

 obtains in the American variety ; for while those that clothe 

 the equatorial region of the body are somewhat the longer, 

 the entire series merge into one another by almost impercep- 

 tible gradations. In this respect the species here introduced 

 may be said to resemble an immature stage of the American 

 type. The great flexibility of the anterior portion of the 

 body is a feature common to the American and Tasmanian 

 species, both exhibiting in a like manner a tendency to roll 

 this region upon itself in the form of a helix. 



An important point that was left undetermined by Dr. Leidy 

 respecting the structure of Trichonympha relates to the precise 

 position of the oral aperture. The bodies of the animalcules 

 are almost invariably filled with fragments of the woody 

 debris devoured by their hosts the white ants, which shows 

 that their sustenance is taken into their body in a solid state, 

 and is not simply absorbed in the fluid form, as occurs with 

 the group of the Opalinidse. A prolonged observation of 

 living examples of the American species remitted me by 

 Dr. Leidy, and likewise of the Tasmanian type here intro- 

 duced, has resulted in my determining that a distinct oral 

 aperture is developed upon one side of the body at a short 

 distance only from the apical extremity. This orifice takes 

 the form of a transverse slit, and is followed by a narrow 

 oesophageal track, 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 thein into 

 a little white of egg. I also have found this material favour- 

 able for their observation, but have gained an additional 

 insight into their life-history by employing 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 



