Organs and Fertilization in Picea excelsa . 361 
often differing in size, and these granules then seem to unite 
into one or more larger ones. At a later stage, about the 
time of fertilization, the proteid-vacuoles, each with a single 
large granule occupying the larger part of the vacuole, are 
often observed. In addition to the proteid-vacuoles several 
granules varying in size can be seen scattered all through the 
egg-cytoplasm. Thus the egg-cytoplasm, which appeared to 
be finely granular before the formation of the ventral canal- 
cell, presents a much coarser structure about the time of 
fertilization (Figs. 33-35, 49-5 1 )- 
The origin of the proteid-vacuoles is not at all clear, 
although there is no doubt about their being a kind of 
nutritive substance. Hirase (’95) observed that the granules 
in the egg of Ginkgo were of nucleolar origin, being derived 
both from the nucleus of the central cell and from the nuclei 
of the sheath-cells. Arnoldi (’00 a) thought that substantially 
the same thing takes place in Cephalotaxus . Ikeno (’98) 
observed the passing in of the substance secreted by the 
nuclei of the sheath-cells, through the numerous pores in the 
wall of the archegonium, into the egg, and he ascribed to this 
substance the origin of the proteid-vacuoles. Arnoldi (’00 b) 
described a remarkable migration of whole nuclei from the 
sheath-cells into the egg in several species of Pinus. 
Murrill (’00) and Miss Ferguson (’01$) have both failed to 
find such passage of nuclear substance from the sheath-cells 
into the egg. In careful examination of numerous archegonia 
in all stages of development, I was not able to find even a 
single case representing such a passage in Picea. 
The mature egg-nucleus, situated at or near the centre 
of the archegonium, usually contains one or more large 
nucleoli and often several smaller ones ; but it is not always 
easy to distinguish the latter from the chromatic granules 
in the nuclear reticulum. The reticulum presents a more 
or less granular appearance and stains violet with the triple 
stain. The nucleus is usually somewhat oval or elliptical 
in shape, its average size being ioo /x by isoju (Figs. 35, 
49-5 1 )- 
