424 
grund in the Great Belt in November it was, however, placed on the 5th or 6th 
joint. The trichoblasts are usually much branched, showing two generations of 
branches, particularly in the vigorous forms growing in shallow 
water (fig. 369 A). In other specimens the ramification is feebler, 
the trichoblasts bearing only one or two simple branches, or 
they may be entirely unbranched. Such simple trichoblasts are 
particularly found in slender specimens belonging to or approach- 
ing to f. {enuis, generally in specimens growing in deeper water 
or in shaded localities. They were met with in most of the spec- 
imens collected in November, at a season when the growth is 
very feeble. They occurred too in several specimens collected by. 
Bornholm in July and August. The trichoblasts are usually hyaline: 
Fig. 366. 
Polysiphonia violacea. 
Tip of shoot treated with in specimens from deep water, however, they may contain feebly 
glycerine. I—IV, tricho- - = 
Has nent een rose-coloured chromatophores. The cells contain one nucleus. The 
numbered according to trichoblasts may be shed early, in other cases they may persist for 
age; >» basal en ofte a fairly long time; thus in several specimens from the Baltic Sea 
they were still present on the 40th to the 42nd joint from the top. 
The primary branches arise at the base of the trichoblasts and develop simult- 
aneously with them. They do not, however, occur at all the trichoblasts but are 
usually separated by 4 or 5 joints; yet, 
two or even three primary branches 
often follow immediately after each | jae 
other. The basal cells of the tricho- 
blasts which are not accompanied by 
primary branches generally produce 
later branches which may be named 
secondary axillary branches. These 
branches arise at a considerable distance 
from the top, usually only when the 
trichoblast has fallen off, but not rarely 
before this has taken place; they may 
attain a considerable length but always 
remain much feebler than the primary 
axillary branches. Very often all the 
basal cells produce branches, though 
some of them reach only a small size. 
Asanexampleis here given a diagram ofa 
shoot, where ¢ signifies trichoblast, ¢ basal Fig. 367. 
cell of a trichoblast fallen off, b primary Polysiphonia violacea. Portion of ‘central and pericentral 
m cell showing nuclei, chromatophores (partly) and pits, p, 
branch and s secondary axillary branch: connecting the central with the pericentral cells. 230:1. 
ssssbsssssbbissssbssssbbtissbssssbbsstsbssssbbssssbbttlibbitibttttbb (top). 
