DEVELOPMENT OF SPERMATOBIUM. 3 1 



Fig. 13. A sporoblast with nuclei in mitosis. 



Fig. 13b &c. micronuclei with chromosomes at end of mitosis. 



Fig. 14. Another sporoblast with single nucleus. 



Fig. 15. A sporoblast in which the centers of the cytospheres are more 

 developed, micronuclei not eliminated. 



Fig. 16a. a sporogonium, with developed sporoblasts, a stage further ad- 

 vanced than the one figured in 10a. 



Fig. 16b. One of the sporoblasts drawn on a larger scale, showing three 

 micronuclei. 



Fig. 16c. A nucleus and a cytosphere of the former. 

 n. nucleus. 

 cy. cytosphere. 



Fig. 17. Two sporoblasts with nuclei in a state of division. A large 

 sporoblast has just divided itself in two almost equal parts. 



Fig. 18a. a smaller, probably final sporoblast with nuclei in mitosis. 

 The nuclei are yet connected by caryoplasm. 



Fig. 18b. One of the cytospheres of the former. 



Fig. 19. A sporogonium of Spermatobium eclipidrili. The nuclei are well 

 scattered out, but remains of nucleoli are seen in two places. 

 The cytospheres have not yet collected into sporoblasts. 



Fig. 20a. a similar sporogonium of Spermatobium Freundi at the same 

 stage of development, Figs. 19 and 20, are drawn under the same 

 magnification and show the relative size of the sporogonia and 

 cytospheres in the two species of Spermatobium. 



Fig. 20b. a groujD of cytospheres. 



Fig. 20c. a cytosphere drawn on a larger scale, both from the sporo- 

 gonium figured in fig. 20. 



Fig. 21a. a sporogonium in which some of the micronuclei are unusually 

 small, by an error of engraver not shown. 



Fig. 21b. a si^oroblast of the same with five micronuclei. 



Fig. 22. A sporoblast with dividing nuclei. These sporoblasts would 

 have further divided. 



Fig. 23. A remaining nucleolus, showing a spherical granulation, sur- 

 rounded by cytospheres. The macronucleus has entirely disap- 

 peared. 



Fig. 24. A sporogonium with partly developed lunate spores. 



Fig. 25. Some of the spores drawn on a larger scale. 



Fig. 26. A shuttle spore with nuclear or nucleolar bodies. 



Fig. 27. A fully developed pseudonavicella spore with beaded margin, 

 nucleus and cytos^jheres. 



Fig. 28. An empty spore of uniisual form. 



Fig. 29. A sporogonium with spores in various stages of development. 

 A central "restkorper" of unused cytospheres. 



Fig. 29b. a sporogonium with shuttle spores and "restkorper." 



