12 ZOOLOGY: KOFOID AND SWEZY 
The spindle fibers are formed from the ends of the paradesmose or the cen- 
troblepharoplasts, pass through the nuclear membrane, which remains intact, 
and the chromosomes become arranged upon the spindle in the equatorial 
plate by a process analogous to that found in Trichonympha. The parades- 
mose is found outside the nuclear membrane (figs. 8, 9) and fades out in the 
late telophase precisely as does that of the other species. 
It is thus evident that these two organisms, though differing widely in their 
general morphological characters, yet follow precisely similar modes of 
mitosis. These similarities consist in the following; Division in both is fun- 
damentally longitudinal, including the splitting of the chromosomes, the 
centroblepharoplast and the entire body. The chromosomes are precocious 
in their splitting, doubling the number which later goes on the spindle. The 
Figs. 6-10. Trichomonas angusta Alexeiefft, after Kofoid and Swezey.* X 1500. 6 
Active motile form prior to division. 7. Late prophase with five pairs of split chromosomes 
centroblepharoplasts connected by paradesmose. 8. Late metaphase; paradesmose outside 
nuclear membrane. 9. Telophase with centroblepharoplasts still connected by parades- 
mose. 10. Mitosis completed, cytoplastic division approaching. Ax., axostyle; c, cen- 
troblepharoplasts; m., myonemes; par., paradesmose. 
centroblepharoplast divides with a paradesmose formed to connect the two 
parts as they separate. The motor organelles are divided with new out- 
growths to complete the full complement of each daughter cell. These 
remain attached to the centroblepharoplasts throughout the entire process 
of division. The nuclear membrane persists, with the spindle fibers passing 
through from the ends of the paradesmose, which remains outside the mem- 
brane. Pseudosynapsis occurs as part of the chromosome cycle in both 
forms. The paradesmose persists through the late telophase stage after the 
rounding up of the daughter nuclei, fading out before plasmotomy occurs. 
Two phases of these processes deserve particular attention. These are the 
formation of the paradesmose and the attachment of the motor organelles to 
the centrosomes. So far as present records go both of these phenomena are 
