Notes on a New Boveria species. 23 



transformed each into a thick spindle, the slender terminal portions 

 of which often anastomose with those of the neighbouring cilia. 



Finally there comes the stage represented by the individual D, 

 which is the most advanced we could observe. Here the entire cyst 

 has grown enormously, measuring about 85 /•« in diameter, about two 

 fifths of w^hich length belong to the diameter of the cyst-proper. The 

 wide pericyst cavity is traversed, as was the case in preceding stages, 

 by innumerable modified cilia. The anastomosis between the last 

 mentioned has now become notoriously intricate. The micronuclear 

 multiplication has advanced very much, the resulting minute nuclei 

 being produced not less than fifty in number. 



We have not been enabled to observe further changes of the 

 cyst lastly described. But it is conceivable that the cyst contents 

 ultimately divide into as many uninucleate bodies as there are 

 nuclei, and the latter are set free probably by dehiscence of the 

 surrounding tissues of the respiratory organ. 



We have not infrequently met with another type of encystment, 

 which we venture to attribute also to Boveria labialis. According 

 to our observations this sort of encystment takes place when the 

 parasites have fallen into the body-cavity, owing probably to 

 breaking off, by some cause or the other, of some portions of the 

 respiratory tree. The above stated seems to be well born out by 

 the fact that the cysts of this sort are most abundantly dis- 

 covered in detached branches of the respiratory tree, freely float- 

 ing in the cœlomic fluid. The parasites penetrate into the connective 

 tissue of the respiratory tree, a peculiarity of this encystment, 

 through the outer lining epithelium of the organ. After penetration 

 the organism contracts its body into a small roundish mass and 

 secretes the inclosing cyst. During this contraction period all 

 visible organellae excepting the micronucleus are lost to sight. Now 

 the micronucleus begins to multiply amitotically. As the micro- 



