440 BOTANICAL GAZETTE [JUNE 
thought of. A different term seems advisable in order to avoid 
the confusion which must arise if it should be introduced into 
botany. 
Mottier? has also reported a transverse division of the chro- 
mosomes in the pollen mother cells of Lilium. He reports that 
the pseudo-reduction takes place in the first division and the 
transverse splitting of the chromosomes in the second. How- 
ever, his evidence is not very conclusive, and his figures are 
rather indefinite, so that it is not possible to judge whether his 
conclusions are justifiable or not. In the case of the reduction 
nucleus of the embryo sac of L. Philadelphicum the divisions 
which form the macrospores are skipped, so I am not able to 
generalize or predict what would occur in the normal process 
where a number of macrospores or microspores are formed. 
If we accept Dixon’s evidence, it seems probable that the 
reduction takes place in the first division of the pollen mother 
cells. In the pollen mother cells of ZL. Jongiflorum, Dixon found 
that during the first division the chromosomes sometimes formed 
a loop which he thinks may be derived possibly from a loop in the 
original chromatin band, and sometimes they are twisted round 
each other. He says that while they lie in the equator the two 
parts of the chromosome are in close contact and seem fused 
together at their inner extremities, and that during metakinesis 
the two rod-like portions part from one another. He says: 
“From the process described it appears probable that each 
chromosome i in this karyokinesis represents two of the previous 
nuclear divisions which have become more or less completely 
united end to end.” “Thus the reduction in number is effected 
_ by an end to end PRES of the chromosomes as Strasburger has 
already suggested.” “The next division by which the pollen 
_ tetrads are formed takes place probably according to the normal 
<a yokinesis i in plant-cells.” 
a8, must be borne i in mind, however, that there is at present 
ey Ss, ae Seniesa. pe Ke ntheilung in den Pollenmutterzellen einiger 
Dae an Maken, Jahrb. £. wiss. ay an 169-204. 1897. 
ies can of Lilium —: Ann. Bot. 9: adios 1895. 
