Neomeris dumetosa , L amour. 583 
circular scars representing the points of attachment of previous 
whorls of similar deciduous lateral appendages. In this speci- 
men the lowest whorl of scars was 4 mm. from, the rhizoid 
portion ; but six other specimens of the same length, though 
slightly older and showing 4-8 whorls of scars, agreed in the 
position of the first scars at a distance of about 2 mm. from 
the base. The first whorls of filamentous appendages are 
formed at varying distances along the main axis ; but as 
growth proceeds, development becomes more regular and the 
length attained by the internodes is fairly constant in the 
growing region. In the older portions, as the tubular axis 
increases in breadth, and the wall in thickness, the internodes 
are correspondingly shortened, and the zones of old scars 
rapidly become pulled down close to one another and finally 
obliterated. It is thus only in comparatively young plants, in 
this first stage of growth, that the first-formed whorls can be 
traced right down the axis, and in such cases there appeared 
to be a general agreement in the first whorl being formed at 
a distance of 1*5 to 2*5 mm. from the basal portion; and 
though the comparative elongation of these young specimens 
at first suggested that they might be merely spindly etiolated 
specimens, owing their poor development to their being crowded 
out by the more mature individuals, their close agreement in 
the structure of the few lower millimetres and the known 
effects of later increase in diameter of the main axis may 
fully justify the acceptance of these as normal specimens ; the 
later apparent slowness in longitudinal extension of the thallus 
as a whole being due to the counterbalancing shortening of 
the basal internodes (Fig. 30). The first stage, therefore, 
marks the direct assumption of the Dasycladus type of thallus, 
and this structure is maintained for many nodes. With in- 
creasing bulk of the axis, the number of appendages in a whorl 
increases (12-18), while the lateral appendages themselves 
reach a higher degree of complexity, ultimately consisting of 
3-4 times di- or trichotomizing filaments, corresponding to 
the c articulated ramelli ’ and c byssoid fibrils ’ of Harvey which 
occur in allied genera. The constituent segments of these 
