III. SPOROZOA: GREGARIXA 



Reproduction typically occurs in an encysted condition (fig. 145, II). 

 Usually two animals occur in a cyst. After each individual has become 

 polynucleate by division of its nucleus, it divides at first superficially, 



T. 



FIG. 145. Different Gregarina. I-VII, development of Stylorhynckus; I, S. 

 longicollis (after Schneider); II, encysted 5. oblongatus (two animals) beginning 

 gamete formation; III, same in later stage, the sexually differentiated gametes in 

 copulation; IV-VII, formation and development of the zygote of S. l/i^icollis more 

 enlarged; IV, copulation of gametes; V, fusion; VI, beginning division; VII, 

 8, sporozoites formed. A. Clepsidrina Uattarum. 1-4, Monocystis magna (after 

 Cuenot). i, two individuals in copulo in the spermatheca of an earthworm, sur- 

 rounded by its spermatozoa; 2, encysted; 3 and 4, parts of cysts, formation and con- 

 jugation of the gametes, more enlarged (according to Brasil the gametes are slightly 

 differentiated sexually), cu, cuticula; dm, deutomerite; ek, ectosarc; en, entosarc; g, 

 gametes; g l , zoospores, g-, oospore; pm, protomerite; n, nucleus; r, residual body: x, 

 sperm of earthworm; z, zygote. 



later internally into small spheres, the gametes (III) . The gametes fuse in 

 pairs to bodies which take a spindle shape and become enclosed in a firm 

 envelope, the spores, zygotes or 'pseudonavicellae' (fig. 145, 4, ^ ' 



