394 K. MASUI: 
bringing about the rapid growth of any region would seem to be concerned 
in coming amitosis.” 
A view different from those of PATTERSON and mine is maintained by 
Wieman (’10 b) who studied the amitotie division of germ-cells in Leptinotorsa 
signaticollis. He says: “What causes the change from mitosis to amitosis ? 
It has appeared to me that here likewise a gradual diminution in nutrition is 
responsible. It might be assumed that the object of the long rest stage or 
growth period in the development of the ovum is to elaborate food and formative 
material for maturation, fertilization'and embryonic development. We might 
further assume that the same process provided for a certain number of 
mitotic divisions extending through the early cleavage. The direct method 
of cell division sets in because of a deficiency in the amount of nutritive 
material (oxygen ?) necessary for continued mitotic divisions. This is in keeping 
with the fact that amitosis occurs usually under abnormal metabolic conditions 
which are unfavorable to normal metabolic processes. Amitosis might be 
regarded as a simpler form of cell division, not so much because it takes 
place in the absence of spindle and chromosomes, as for the reason that it 
can occur under circumstances that makes mitosis impossilbe.” 
B. THE SYNAPSIS AND THE REDUCTION. 
As far as I am aware, there are comparatively few complete accounts of 
the synapsis and the reduction of chromosomes in any mammal at the present 
time. 'The researches of Mrves (’98), GuyER (10), STEVENS (’11), WODSEDALER 
(13, ’14) and others have chiefly dealt with individual sections of the process, 
with the origin of the archosome ; the history of the centrosomes in relation 
to the spermatozoa; and the behavior of the accessary chromosomes. Only 
WINIWARTER (01) and Jorpan (11) demonstrated the subjects accurately. 
JORDAN (11) in opossum found that during the synizesis the first 
numerical reduction of the diploid group of chromosomes occurs apparently by 
telosynapsis, where he states: “The character of the early prophase chromo- 
somes (double threads ; later loops and paired threads) suggests that perhaps 
no sharp distinction really exists between the end-to-end and side-to-side 
method of conjugation. Here the one appears to follow the other. The 
reduction takes place first by end-to-end conjugation. Later on, the limbs of 
