GREGARINIDA. 57 



nucleus lies in the deutomerite. In such forms there is generally 

 a small third division of the body in front of the protomerite 

 called the epimerite. It contains a small quantity of endoplasm, 

 and is the part of the body by which attachment to the cell-Jiost 

 is effected. When the animal loses this attachment and lies free 

 in the alimentary canal the epimerite disappears. 



The epimerite varies much in form, and bears appendages of very 

 different kinds (hooks, spikes, filaments, etc.). It is usually found 

 only in septate forms (with a proto- and deutomerite), but occasionally 

 it is present on the front end of a monocystid (non-septate) form. 



Occasionally after detachment from their cell-host they penetrate 

 the gut-wall, and form cysts which project into the body-cavity 

 these are known as the body-cavity forms ; but as a rule they lie 

 freely in the alimentary canal. 



Free Gregarines particularly the Polycystid (septate) forms 

 have a peculiar habit of adhering to one another, end to end, in 

 rows (Fig. 45). These are the so-called associations of Gregarines. 

 As many as a dozen may be so joined together. The anterior indi- 

 vidual of an association is called the primite, the rest the satellites. 

 The phenomenon has nothing to do with conjugation. 



Nourishment is effected by endosmosis through the body-walls, and 

 motion is confined to a slow gliding forward of the body. The body, 

 however, has sometimes the power of change of form, though such 

 change is not of an amoeboid character. It consists rather of a 

 contraction of the ectoplasm which causes movements of the endo- 

 plasm, and is not unlike the streaming movements seen in the 

 Myeetozoa. 



In many forms there are longitudinal fibrillar thickenings of the 

 cuticle, and occasionally a special superficial layer of the ectoplasm 

 immediately beneath the cuticle is distinguished as the sarcocyte. 

 The sarcocyte, which is sometimes found only on the anterior part 

 of the body, may contain a layer of transversely-placed fibres, which 

 are very possibly contractile in function, and form the part of the 

 ectoplasm called the myocyte. 



Reproduction is effected by the division of the body while in an 

 encysted condition into spores, and seems generally, if not univer- 

 sally, to be preceded by conjugation of two or more individuals. 

 The procedure is as follows : two (rarely more) individuals apply 

 themselves together in various ways, and gradually flatten out against 

 one another so as to form a rounded syzygium. In some cases, 

 after remaining in this condition for some little time, it appears 



