SPOKOZOA 



751 



ectoplasm, the so-called ' myocyte ' which he has found to consist of 

 a layer of contractile fibrils. When the process of encystation com- 

 mences we find that, whatever the original form of the body may be, 

 it becomes globular, ceases to move, and becomes invested by a 

 structureless ' cyst,' within which the substance of the body under- 

 goes a singular change. The nucleus disappears, and the sarcodic 

 mass breaks up into a series of globular particles, which gradually 

 resolve themselves (as shown at ft, c, d, e, fig. 583) into forms very 

 like those of Namculw, and a .cyst more advanced, and greatly 

 magnified, is shown in fig. 582. These ' pseudo-navicella? ' or 

 ' spores.' as it is better to call them, are set free in time by the 

 bursting of the capsule that incloses them ; and they develop them- 

 selves into a new generation of Gregariiue, first passing through an 



FIG. 583. Gregarina Scenuridis, from testis of Tubifex rivulorum, 

 two adults uniting : a, succeeding stage ; b, encystation stage ; in c 

 and d the contents are seen breaking up; in e the characteristic 

 nseudo-navicellar form has been acquired by the spores. (After 

 Kolliker.) 



amoeba-like stage. A sort of ' conjugation' has been seen to take 

 place between two individuals whose bodies, coming into contact 

 with each other by corresponding points, first became more globular 

 in shape, and are then encysted by the formation of a capsule around 

 them both ; the partition-walls between their cavities disappear ; 

 and the substance of the two bodies becomes completely fused 

 together. But as the products of this * zygosis ' are the same as that 

 of the ordinary encysting process, there seems no sufficient reason 



