LEVINE: CyTOLOGY OF HYMENOMYCETES 159 
At this stage I have also found another type of fibrils in the 
cytoplasm. These latter run irregularly but in the main length- 
wise of the basidium. It may be that they are indications of 
cytoplasmic streaming. 
_ As the sterigmata bud out (PL. 6, FIG. 34, 35, 74) the centrosomes 
and strands are carried upward; the centrosomes remaining at 
the apex of the sterigma. In mature sterigmata (PL. 7, FIG. 36, 78) 
the granule lies at the apex and the nucleus is still attached to it by 
the fibrillar strands. In this stage of development the four nuclei 
are found at or below the middle of the basidium (PL. 5, FIG. 37) but 
do not show any indication of fusing as Wager holds for Stropharia 
stercoraria. A small globular mass of cytoplasm, the spore initial, 
now appears at the end of each sterigma (PL. 7, FIG. 38). The 
growth is rapid; later stages are shown in FIG. 39, 40, PL. 7. On 
the upper, inner surface of the spore wall the centrosome is still 
visible (PL. 5, FIG. 41) and from it the fibrillar strand passes down 
through the sterigma to the nucleus in the basidium. It seems 
that the centrosome marks the apex of growth for the spore as well 
as for the sterigma. In the spores of B. castaneus (PL. 7, FIG. 75) 
a number of fibrils radiate downward from the centrosome through 
the cytoplasm but the strand which runs to the nucleus is thicker 
than the others. 
These fibrillar strands connecting the nuclei with the sterigmata 
and spores are present in practically all the Boleti I have studied. 
In the basidia of Merulius tremellosus I have also observed them 
extending from the apex of the spores to the nuclei below in the 
basidium. In Polyporus brumalis and P. lucidus I could trace 
them only from the sterigmata to the nuclei. 
Simultaneously with the development of the spores the nuclei 
begin to move towards the sterigmata. This migration is probably 
the result of the contraction of the kinoplasmic fibrils as claimed 
by Maire (1902). In FIG. 63, PL. 7, of Boletus albellus the nucleus 
is shown part way through thesterigma. Inthe same spore higher 
up another spherical, red staining body appears. Its lower por- 
tion is attenuated forming a long, strand-like fibril which extends in 
the direction of the nucleus. What the nature of this body is 
have not been able to determine. 
The nucleus (PL. 8, FIG. 64) divides soon after entering the spore 
