42 
The Ohio Naturalist. 
[Vol. VII, No. 3, 
similar contractions in other reduction cells, as microsporocytes 
and megasporocytes, or any other cells, in which a similar phe¬ 
nomenon is observed. Accepting this terminology as conducive 
to lucidity of expression, synapsis will then normally mean the 
process by which two univalent chromosomes become united to 
form one bivalent chromosome; or, in case a continuous spirem is 
formed by the end to end conjugation of univalent chromosomes, 
the process by which two univalent chromosomes become so 
united that at the time of the transverse segmentation of the 
continuous spirem they do not break apart as in previous divi¬ 
sions but are brought into the mother star as single bivalent 
pieces. 
This will then include the idea expressed by the term, pseu¬ 
do-reduction, which refers only to the fact that half as many 
chromatin pieces are present as in the previous division. Syn¬ 
apsis must not be confounded with the fusion of chromosomes in 
the network during each 1 'esting period nor with the ordinary 
fusion by which a continuous spirem is produced. 
Recently the writer has studied a considerable number of 
preparations in order to refresh his mind upon this subject. The 
few figures presented are given merely as examples of a very 
large number of distinct types of chromatin contraction, which 
may be observed. 
Some confusion has been produced by the use of the terms 
longitudinal and transverse division. Evidently it is of no im¬ 
portance whether two entire univalent chromosomes conjugate 
to form a ring, a twisted loop, or a simple longitudinally united 
or folded pair, so long as they separate during metakinesis. 
Transverse division means a qualitative division, longitudinal 
division a quantitative division. In such bivalent chromosomes 
as occur in the megasporocytes of Lilium philadelphicum (fig. 1), 
and Erythronium ulbidum and americanum , and in the micro¬ 
sporocytes of Lilium tigrinum the two limbs of the chromosomes 
lie folded on each other and twisted together. But the real 
reduction division is not so much the pulling apart of the two limbs 
but the transverse break in the loop at the head of the chro¬ 
mosome which is supposed to represent the point of the synaptic 
fusion of the pair of univalent maternal and paternal chromo¬ 
somes. 
Synapsis and reduction then are simply processes by means 
of which entire chromosomes, presumably maternal and paternal, 
are segregated into the daughter nuclei; or by which at least qual¬ 
itative division of the chromatin is accomplished in case there is 
a mixing of paternal and maternal chromatin during the “2x” 
phase of the organism. The whole process appears to be merely 
a mechanical contrivance for bringing about qualitative separa¬ 
tion. We may consider chromosome reduction as a necessary 
