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distarxce 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 them 

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

 favourable for their observation, but have gained an addi- 

 tional 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 nutri- 

 ment, their pharynx and digestive cavity being frequently 

 found densely packed with its component corpuscles after 

 their immersion in this fluid for a short interval. 



As with the American species TricJionympJia Leidyi is 

 represented in its earlier and immature conditions by a host 

 of polymorphic forms that diifer greatly in aspect from the 

 adults. The youngest observed are of an ovate contour, and 

 clothed throughout with cilia of even length. These young 

 individuals gradually increase in length until their long 

 diameter may equal or even exceed four or five times their 

 greatest breadth, the cilia in the more advanced phases being 

 longest posteriorly, while the surface may be obliquely 

 furrowed in opposite directions. It is in connection with 

 this transitory condition that I have observed the pheno- 

 mena of propagation not hitherto recorded. This is effected 

 by a process of transverse fission, division taking place 

 towards the anterior region of the body along two intersecting 

 furrows. The anterior of the two separated moieties assumes 

 a pyriform outline, and grows speedily to the parent shape, 

 while the posterior one retains its primitive attenuate fusiform 

 contour, and may continue to multijoly by fission. 



When placed in diluted milk the animalcules of both the 

 American and Tasmanian species of Triclionym2)licchn.Ye been 

 observed by me to assume a fixed condition that has not 

 hitherto been described. An attachment to the surface of 

 organic substances or other convenient fulcra, is then accom- 

 plished through the medium of the long fascicle of hair-like 

 cilia that are produced from their posterior extremity. These 

 cilia intersecting one another at a short distance from the 

 body form a sort of hollow cone, the expanded base of which 

 grasps the selected fulcrum of support after the manner of 

 an acetabulum. This habit of, as it were, anchoring them- 

 selves by their long caudal cilia was observed of both the 

 adult and immature animalcules. No trace of the structure 

 common to all higher Infusoria known as the contractile 

 vesicle has been detected in connection with Tricoiiympha 



