2 Miyake, The development of the gametophytes etc. 
gaps left by Am oldi and thus to complete, as far as possible, 
the history of the gametophytes and embryogeny of the genus. 
Cunninghamia sinensis, which was the only member of the 
genus, until the recent discovery in Formosa, disclosed the presence 
of a sister species C. Konishii (Hayata, 1908), is a native of 
China and is fonnd in Japan only in the cultivated condition. The 
material for the present study was collected chiefly by myself 
during the last four years 1905—1908 from plants growing in 
Kyoto and Tokyo. A few materials which had been collected by 
Prof. K. Shibata before the year 1905 and kindly given t6 me, 
were also examined. 
The material was obtained from different trees, and from 
several cones of the same tree at each collection, and the fixing 
was done immediately after the collection. The staminate cones 
were fixed entire or cut into several pieces according to their sizes. 
In the early stages of development the ovules were fixed with a 
part of the scales, and later the ovules were entirely removed 
from the scales. For older stages, a part or the whole of the 
integument was removed’ before fixing. 
Flemming’s chrom-osmo-acetic acid solution of various con- 
centrations was chiefly used for fixing, but chrom-acetic mixture 
was also occasionally used. After fixing, the material was washed, 
dehydrated and imbedded in paraffin in the usual way. The sections 
were cut usually from 5 to 10 jui in thickness. For staining, 
Flemming’s safranin, gentian violet, and orange combinatio.n or 
Heidenhain’s iron-alum haematoxylin were used. 
Development of the Pollen. 
The staminate cones make their appearance, at or near the 
tips of the branches, as early as September of the year preceding 
pollination. The mature cones at the time of pollination is shown 
in text-figure 1. Young microsporangium, as observed in early 
November, has the wall consisting of two or three layers of cells 
and just within, in immediate contact with the archesporium, there 
is a layer of tapetum-cells. The archesporial cells are found in 
constant division during the autumn and the pollen mother-cells 
are formed before the end of the year. 
The division of the pollen mother-cell takes place (in the 
middle part of Japan) about the end of February or the beginning 
of March. The pollen mother-cell, whose nucleus is in a resting 
condition, is shown in Fig. 1. As the cell prepares for division, 
the contents of the nucleus undergo a synaptic contraction (fig. 2). 
Then follows the spirem stage (fig. 8). The thin spirem thread 
gradually thickens itself and the double nature of the thread be- 
comes more or less apparent (fig. 4). The thick spirem now 
segments into Chromosom es (fig. 5). The stages between synapsis 
and chromosome-formation are now considered as the most important 
phases in the reduction-division, and have been investigated with 
special care by several cytologists during last few years. The 
