On a new Sporozoon from tlie vesicul;« semluales of Perichaeta. 7g5 



considerable size and provided with a large nucleolus. The logwood 

 stain had not affected , the nucleus itself, but had tinged the nucleolus 

 of a yellowish brown. 



In glycerine preparations (fig, 7 a) a Single nucleus was frequently 

 Seen when it happened to be situated in the taillike process of the 

 Gregariue; in such preparations no nucleus could ever be seen in the 

 central region owing to the great thickness of this part. In other in- 

 dividuals transverse sections showed numerous nuclei scuttered through 

 the parasite; these were smaller and had an obvious nucleolus; they are 

 no doubt produced by (he division of the at first Single nucleus. This 

 very early stage in sporulation is unfortunately the only stage which 

 my preparations afford. 



In one instance (fig. 14) I was so fortunate as to notice the 

 formation of karyokinetic figures in nuclear division. 

 I believe that this process has as yet been observed in but few Gregari- 

 nidae. I am disposed however to value this discovery not at all with 

 the idea that_it is of great importance, but because it appears to show 

 that'my specimens'"are well preserved and that I may therefore have 

 confidence in describing the details of the structure of this form. 



The division of the nuclei in the encysted parasites is accom- 

 panied by a division of the cyst contents which are separated into a 

 number of masses, much fewer however in number than their nuclei. 



3) Young stages. 



In fig. 83 are presented a number of small Gregarines from the 

 vesicuhe seminales of the same earthworni which I regard (at least 

 for the present). as young stages of the same parasite; the figure 

 comprises Sketches of a series of individuals indicating the principal 

 forms which I observed. 



It will be noticed that the general shape is oval or round 

 with one or two long processes; where there are two processes 

 one is considerably longer than the other. 



It may be that these different shapes are merely due to the fact 

 that the parasites were killed when in movement, and were therefore 

 fixed in different attitudes. But it seems more likely that this is not 

 the case. 



The resemblances between my figures and those which van Be- 

 neden (5) gives of a corresponding stage in Porospora gigantea is 

 not a little striking. This resemblance cannot however be more than 

 superficial; there can of course be no „pseudofilaria" stage since the 



