308 M. A. Schneider on Oplnyocystis Biitsclilii. 



simple types that everybody precedes with a Proto, and I was 

 about to make a Protocystis, or something of the sort,— ray 

 first proto. But I was obliged to abstain from inscribing 

 that date in my life, when the expulsion of the four nuclei 

 suggested the idea that, instead of a form which could be 

 regarded as primitive, I had undoubtedly only a degenerate 

 product, the result of a number of transformations which only 

 leave to Ophryocystis a borrowed and deceptive simplicity. 

 In the Myxosporidia the whole of the protoplasm and nuclei 

 divides first of all, according to Biitschli, between the two 

 spores. 



It is under the influence of these very sage considerations 

 that I shall commence by describing the exception, seeing 

 that the exception may very well be only a former rule. 



Exceptionally, then, there is a tendency to the formation 

 of two spores, as is normally the case in the Myxosporidia. 

 Figs. 39 and 40 represent this stage, which is comparatively 

 very rare. Fig. 39, drawn from the life, is particularly 

 instructive. The mass of the cyst remains divided into two 

 hemispheres, and each hemisphere has formed a spore and a 

 residual mass, which are as distinctly separated as possible 

 from each other. The two spores and the two residual 

 masses are placed diagonally. If we had not this residual 

 mass we should therefore have a bisporic capsule, like those 

 of the Myxosporidia. 



When things take place as just described it is not usual 

 for the two spores to come to perfection ; nearly always one 

 of the two thrives more than the otlier and alone arrives at 

 maturity. Nevertheless there are cysts which contain both 

 their spores, although want of space has prevented my giving 

 a drawing of one. 



Pretty often, also, it happens that one of the hemispheres 

 alone forms its spore on its own account, the other remaining 

 barren. Fig. 37 represents a case of tliis kind, and it will be 

 seen at once that the barren hemisphere has retained its three 

 nuclei, and that in the other a single nucleus has passed 

 into the constitution of a small spherical spore. Five nuclei, 

 therefore, are abandoned as residue. 



But the usual case is that in which, a single spore being- 

 formed, it is the common product of the two halves of the 

 cyst, each having a fractional participation in the formation 

 of the reproductive element. I'he spore then appears in the 

 centre of the cyst, and it acquires a volume at least double 

 that of the dwarfish spores Avhich we have just been con- 

 sidering. 



Fig. 41 eho^\ s, in tlie fresh state, a cyst of which the spore 



