Neomeris dumetosa, L amour. 587 
without any pronounced adhesion of cell-membranes (Figs. 
12, 14, 16). The contrast between the branched 4 assimilating 
filament ’ and its expanded basal segment is now very 
marked, and the terminal portions henceforth assume the 
appearance of mere hair-like appendages ; but it must be 
carefully noted that their morphological value will remain 
unaffected. When these terminal portions become detached, 
the axis remains clothed by a pseudo-parenchymatous one- 
layered cortex (Fig. 14), the constituent members of which 
differentiate into pedicelled vesicles, and exhibit a single scar 
as in Stage II (Figs. 14, 16). In the older parts of the axis, 
they again become isolated, and gradually fall away, leaving 
as in previous stages their whorled attachment-scars on the 
main axis (Fig. 13). Cases of reversion to Stage II frequently 
occur ; very generally, a dozen or more whorls of the second 
type may be intercalated after 12-20 whorls of Type III ; 
but reversion becomes rarer once the type has become long 
established. 
A median longitudinal section of the apex at this period 
shows that the structure, attained by the plant after an 
average of 100 nodes, is recapitulated in about 5 nodes 
at the actual growing-point (Fig. 15) ; thus, delimitation of 
the basal portion, characteristic of Stage II, occurs in the 
third whorl behind the apex of the main axis ; the dilatation 
of the lower segments results in lateral contact being com- 
plete at the fifth node ; and in a few more internodes the 
form characteristic of Stage III is attained (Fig. 16). 
As examples of the extent to which Stage III is retained 
in the life-history, the following may be taken : one specimen, 
possessing traces of Stage II on 25 whorls of scars, after- 
wards developed 98 whorls of Stage III ; the apex still 
continuing the formation. This was the highest number 
observed. On the other hand, 11 specimens, retaining traces 
of Stage II on the lower scars, while the apical whorls were 
in Stage IV, and whose length varied from 14-19 mm., showed 
7-77 whorls of Type III. Thus, an average plant might 
have formed 43 whorls of Stage III and be passing on to the 
s s 2 
