DIMA8TIGAM(EBA GRUBERI 265 



commenced. This would be in agreement with what is known to occur 

 in other flagellates, in which the first stage of division of the organism 

 is division of the blepharoplasts. These appearances suggest that the 

 blepharoplasts are present in the cytoplasm even during the amoeboid 

 phase of the organism. They are so minute that, unless their connection 

 with the flagella can be detected, it is impossible to distinguish them from 

 other granules which occur in the cytoplasm. It seems probable that in 

 the amoeboid phase they are adjacent to, or actually upon, the nuclear 

 membrane, and that when flagella are to be formed they move towards 

 the surface of the body, retaining in many cases a connection with the 

 nuclear membrane. There seems to be no real evidence that they are 

 derived from the karyosome of the nucleus. Exceptionally only one 

 flagellum is developed by uninucleated amoebse, and three by binucleated 

 or even uninucleated amoebse. 



The amoebse themselves, judging from cultures commenced from a 

 single individual, vary in size from about 5 to 20 microns (Figs. 61 and 121). 

 They are fairly actively motile, and usually form blunt pseudopodia, but 

 sometimes fine hair-like or radiating pseudopodia are produced, giving the 

 organism the appearance of a Heliozoan. The nucleus contains a large 

 central karyosome connected with the nuclear membrane by radiating 

 septa which traverse the clear space. On the inner surface of the nuclear 

 membrane, and just internal to it, is a layer of granules of chromatin. The 

 amoeba3 are difficult to recognize from others of the genus Harlmannella, 

 unless the stages of nuclear division, the cysts, or the production of 

 flagellates can be observed. The nuclear division has been described 

 above (p. 103). The cysts are spherical structures, which in uninucleated 

 forms vary in size from 5 to 12 microns. Their most characteristic feature 

 is the presence of a number of pores in the cyst wall, which is composed of 

 a double membrane (Fig. 121). On agar plates not only do the uninucleated 

 amoebse encyst, but also the multinucleated forms, which produce corre- 

 spondingly larger cysts with an increased number of pores. Cysts from 

 12 to 18 microns in diameter have usually two nuclei, while larger ones 

 have more. Thus a cyst 31 microns in diameter had three nuclei and 

 twenty to thirty pores, while another was 21 microns in diameter, had 

 six nuclei, and fifteen to twenty pores. The cytoplasm of encysted forms 

 contains a number of conspicuous refractile bodies which may be larger 

 than the nuclei. They stain black with iron hsematoxylin, and are probably 

 of a volutin nature. 



1-7. Various forms of biflagcllate type. 

 8-10. Forms with single nucleus, four flagella, and tAvo pairs of blepharoplasts. 

 11-12. Forms with dividing nuclei, four flagella, and two pairs of blepharoplasts. 

 13-14. Forms with two nuclei, four flagella, and two pairs of blepharoplasts. 

 15. Form with four nuclei, eight flagella, and corresponding blepharoplasts. 



