178 J. J. LISTER. 



disposition suggests that they have been set free by the breaking up of a 

 compound nucleus. Optical section. Picro-carmine. 



Fig. 22. X 1460. Part of a section of a nucleus whose nucleoli contain 

 many vacuoles. 



Fig. 23. X 250. Specimen with a " flushed" region of the protoplasm 

 at one end of the nucleus, due to the presence of minute stained particles. 

 Picro-carmine. 



Fig. 24. X 250. Specimen showing "fragments" lying in the cham- 

 bers through which the nucleus has passed, and in those immediately 

 beyond it. In this figure the fragments have been somewhat over- 

 emiihasized, they are generally much less conspicuous. 



Fig. 25. X 1460. Sections through such fragments as those shown in 

 fig. 24. In this case they contain nucleoli, a and b are consecutive 

 sections of the same fragment. Picro-carmine, hsematoxylin. 



Fig. 26. X 230. A nucleus which has lost its rounded form. 



Fig. 27. X 250. The whole of the protoplasm, except that occupying 

 the last two chambers, has broken up into small nucleated spheres, having 

 a diameter of 2-5 to 3/^. At c, a portion of the spiral canal, which lies in 

 the umbilical region, is seen filled with similar spheres. Picro-carmine. 



Fig. 28. X 1275. Part of a section of the same specimen as that in 

 fig. 27. The nuclei which lie in the sj^heres are seen to be in process of 

 karyokinetic division. Picro-carmine and haematoxylin. 



Fig. 29. X 487. Section of nucleus with few and irregularly outlined 

 nucleoli. Flemming's fluid. Safranin. 



Fig. 30. X 730. Section of the terminal chamber of a specimen of 

 the megalospheric form, in which the large nucleus has disappeared, and 

 numbers of small nuclei 1 to l'5;i in diameter are distributed in groups 

 through the protojDlasm. Picro-carmine and haematoxylin. 



Fig. 31. Part of a section through a specimen of the megalosi^heric 

 form, in which the large nucleus has disappeared and numbers of small 

 vacuolated nuclei are distributed through the protoplasm. The structure 

 of the protojilasm is not represented. Zeiss ^ oil. 



Fig. 32a. X 460. Section of a specimen of the megalospheric form in 

 which the whole protoplasm is broken up into zoospores, having a diameter 

 of 3 to 4 fx. A broad communication is seen to connect chambers 2 

 and 10. 



Fig. 326. X 1460. Groups of zoospores in the terminal chambers ; 

 indications of flagella are seen. In the left-hand group of zoospores the 

 nuclei have not taken the stain. 



Fig. 33a and b. x 1200. Actively mo\'ing bodies which emerged from 

 a specimen of PolystomeUa crispa. Probably they belonged to another 

 organism. 



