THE SPOROZQA 



179 



or satellites may become modified in structure. In segmented 



forms this alteration affects chiefly the protomerite, which may be 



reduced or even absent. Thus in the genus Didymophyes syzygies 



of two individuals are 



formed in which the 



satellite loses its 



protomerite entirely, 



so that the resulting 



combination looks like 



a three - chambered 



Gregarine with two 



nuclei (Fig. 25, a). 



Although in many 

 cases the syzygies 

 appear to be tem- 

 porary attachments 

 which have no con- 

 nection with the sub- 

 sequent reproductive 

 phenomena, it is prob- 

 able that as a general 

 rule they represent 

 associations of indi- 

 viduals destined to 

 form conjugating 

 gametes as described 

 for Monocystis, especi- 

 ally in those cases 

 where the union of 



FIG. 24. 



a, Eirmocystis ventricosa, Leger (par. Tipula 

 spp.). b and c, E. polymorpha, Leger (par. Lim- 



ia, larva). Associations of two, three, and 

 five Gregarines. p, primite ; s, satellites. (From 

 Wasielewski, after Leger.) c 



primite and satellites 



is an intimate one, as in Didymophyes and others. Having regard 

 to the manner in which conjugation takes place, there is no reason 

 why any number of sporonts or. gametocytes should not come to- 

 gether to form gametes within a common cyst, and the presence 

 in a cyst of more than two sporonts appears to be of frequent 

 occurrence in some species. 



The body of a Gregarine trophozoite always consists of cuticle, 

 ectoplasm, and endoplasm containing a nucleus, but each of these 

 parts are subject to considerable variation in structure. 



The cuticle or epicyte is a membrane secreted by the ectoplasm, 

 usually of some thickness, and appearing doubly contoured in 

 optical section (Fig. 26, c). Sometimes it can be broken up into 

 fine vertical lamellae corresponding to the ridges presently to be 

 described on the external surface. As has been said above, the 

 cuticle is often produced into hooks or spines or other organs of 

 fixation, especially on the epimerite. On the other hand, all such 



