424 MISS E. 8. BARTON ON NOTHEIA ANOMALA. 
the cells of the host, forming knots of irregularly shaped cells, 
with long thin prolongations ruuning in all directions. In early 
stages these rhizoids are seen only at the base immediately below 
the young shoot, but later many of the cells which lie along the 
sides of the pseudo-cryptostoma give off rhizoids in the form of 
thin prolongations (Pl. 14. fig. 14). It is only by following 
carefully the various stages of the junction of Hormosira and 
Notheia that it is possible to detect the line of demarcation 
between the two in a mature stage. The shoot of Notheia has 
widened exceedingly at the base, and the host has grown in pro- 
portion round it. In most cases the host-cells immediately 
adjoining Notheia have lost their colour, and it has generally 
been supposed that the line of demarcation corresponded with 
the change of colour. But this ‘is not the case, for though the 
tissues of both plants are very much alike, it is possible to see, 
among the colourless cells, a slight irregularity which marks the 
line of contact of Notheia and its host (Pl. 14. figs. 15 & 16). 
It has not been possible to determine whether the contents of 
the Hormosira-cells, immediately adjoining the JVotheia-shoot, 
have lost their colour through the action of the rhizoids which 
have passed down between them ; but the fact that age increases 
both the length of the rhizoids and the depth of the colourless 
layer of Hormosira-cells leads one to suspect some connection 
between the two. I have never seen a genuine instance of the 
penetration of a Notheia-rhizoid into one of the host-cells, though 
many preparations have led me to think this not improbable. Tt 
is, however, a point which can only be worked out with satisfac- 
tion on fresh material. 
The early stages in the life-history of N. anomala bring to 
mind the figure and description of young adventitious branches 
from the basal dise of Fucus vesiculosus, as described and figured 
by Prof. Oltmanns (in Bibl. Bot., Heft 14, p. 73, tab. 13. figs. 
10-13). Here, of course, there is nothing of a parasitic nature 
to be considered as in Notheta, but there is a certain similarity 
in the process of the actual growth. As the result of an injury 
to the thallus, a few cells within the tissue begin to divide 
and shortly form a small protuberance. This grows up in a 
radial direction through the surrounding tissue, the apical cell 
sinks into a depression, and the branch continues to grow in 
the normal fashion. 
