LTFE-CYCLE OF " CTSTOETA " IT^EEOrLARIS (miNCH.). 57 



wlien the spore is swallowed, thus allowing the sporozoites to 

 be liberated. The two membranes, which together constitute 

 the spore-wall or sporocyst, are now easily discernible {ex. and 

 end.). The spore-residuum {s.r.) is also very prominent, 

 occupying the central part of the spore. Now and again 

 (fig. 61 ft) the rim of the outer funnel shows a distinct tendency 

 towards angularisation or serration. 



I have nothing to add to the observations of Minchin 

 (loc. cit.) regarding the eight-nuclear stage and the structure 

 of the sporozoites, and will therefore refer readers to his 

 description and figures. 



C. minchinii. — After repeated and prolonged examina- 

 tion, I have at length succeeded in making out the general 

 appearance of the spores of C. minchinii sufficiently well to 

 assure mj^self that, as regards form, they agree fundamentally 

 with those of C. irregularis. A ripe spore of C. minchinii 

 (fig. 62) is, however, much smaller than one of C. irregularis. 

 Comparing fig. 62 ft with fig. 61, which shows spores of 

 C. irregularis drawn to the same magnification, it will be 

 seen that the lineal measurements of a spore of C. min- 

 chinii are approximately only half those of one of the latter 

 parasites. The shape of both is, nevertheless, strikingly 

 similar. The only difference that need be noticed is that 

 there appear to be two (possibly more ?) delicate, curved pro- 

 cesses in connection with the rim of the funnel. I do not 

 feel so certain about this point as I should like to be, owing 

 to the very few cases in which I have been able to see the 

 entire longitudinal outline of the spore in my sections.^ 



I have been quite unable to distinguish any division of the 

 sporocyst into exo- and endospore. In short, the delicacy of 

 the spore-membranes in C. minchinii is much greater than 



^ The spores are so numerous, so small, and so closely packed in tlie cyst 

 that it is a most difficult matter to find one cut perfectly longitudinally. 

 Moreover, in all the material examined, only twice besides have I found spore- 

 containinf^ cysts. These were both crushed instead of being sectioned. 

 Unfortunately, however, tliey were from spirit-fixed Cucumarise, aud the 

 spores proved to be so crinkled and warty in outline that Ihey were not worth 

 drawing. 



