44 
F. O. BOWER. 
•It does not open till the apices of the hairs reach the swollen 
mass, which closes it and push their way through it. The 
mass itself has been previously undergoing a process of 
disorganisation and swelling similar to that which takes 
place at an earlier period around the central column. 
Seeingthen that, i, in their development these two structures 
are so similar; ii, that Fasergrlibchen do not occur 
among the sexual conceptacles on a fertile branch, t. e, the 
metamorphosis ” is complete ; iii, that no function has 
been assigned to the Fasergriibchen, except that they act 
physiologically as root hairs (Reinke, loc. cit., p. 321) ; iv, 
that they are completely absent from some plants, e. g. 
Halerica (Reinke, loc. cit., p. 360) and Himanthalia lorea ; 
I think the homology of the two structures is so clearly 
proved that I shall be justified in proposing instead of a 
translation of the German word Fasergriibchen,” we 
should use the name neutral conceptacle ” to denote 
these neutral structures. This may be objected to as a con- 
tradictory term, but I think it is important to convey at once 
the relation which appears to exist between them and [the 
true conceptacle. Since, however, the term conceptacle has 
now obtained a morphological rather than a physiological 
significance, the absence of the main function can hardly be 
taken as ground for refusing the term. 
Fucus platycarpus. 
The sexual conceptacles (^. e. those developed on the 
swollen branches) show in their earliest stages a structure 
corresponding closely with that of the sexual conceptacle of 
F. serratus, having an initial cell, terminating a basal series, 
which may, as in .F. serratus^ be traced into the substance of 
the thallus. In later stages, however, the initial cell appears 
in some cases to retain vitality and to divide, forming a 
central hair, of which the apical cell is partially decomposed 
and shrivelled ; in other cases it remains inactive, and 
decomposes as in F. serratus. The central column is not 
so clearly marked as in F. serratus^ since it is very soon 
thrown off, owing to the early formation of hairs lining the 
cavity. For the same reason the identity of the initial cell 
is often lost at an earlier stage than in F. serratus. The divi- 
sion of the basal cell appears to be less definite and regular 
than in the former species. 
In no point of importance were the neutral conceptacles 
found to differ from the sexual ; the hairs are formed earlier 
from the lining tissue than in the sexual conceptacles. 
