RHINOSPORIDIUM KINEALYI. 527 
fully for a similar protoplasmic layer in the larger cysts, but 
have not succeeded in detecting it. Probably thinner sections 
of better preserved material would reveal at least traces of 
it. For showing up the smaller cysts Delafield’s hema- 
toxylin proved to be an excellent stain, as it coloured the 
cysts and their contents blue, while leaving the surrounding 
tissues unaffected. By means of this stain we were able to 
find still smaller cysts with thin walls and granular pro- 
toplasmic contents (fig. 2). The granules in them are of 
varying size, and some of the larger granules probably 
represent nuclei. Similar small cysts were also found in the 
slide stained with picrocarmine, which in many cases were of 
irregular outline, or even showed pseudopodia-like processes, 
giving the organism a resemblance to a small amceba with a 
clear envelope (fig. 4). These irregular forms were stained a 
yellow colour by the picrocarmine, and a slight concentration 
of the tissues round them was observable. A similar body 
was observed in a preparation stained with Delafield’s hema- 
toxylin, but this stain appeared to cause a certain amount of 
shrinkage and wrinkling in the cyst-wall (fig. 3), a result 
observed also in other instances—for example, in the mem- 
brane of the spore-morule (fig. 10). Finally, it should be 
mentioned that we have also found ruptured cysts, showing 
mechanical infiltration of the granular bodies into the sur- 
rounding tissues, as already noted by Vaughan (1). This 
appears to occur chiefly in places where the submucous tissue 
is in process of degeneration. 
4. Systematic PosITvIOoN OF THE PARASITE. 
In the foregoing we have set forth the facts observed in a 
purely objective manner, so far as possible. It will now be 
useful to recapitulate and summarise our observations, and to 
construct what appears to us to be the developmental sequence 
of events, as a preliminary to the discussion of the affinities 
of the parasite. 
(1) The youngest forms we have observed with certainty 
