1899] DEVELOPMENT OF HOLDFASTS OF FLORIDEA 251 
Polysiphonia violacea (Roth) Grev. In a few hours after they 
ae sown, both carpospores and tetraspores attach themselves 
to the substratum by a coarsely granular, mucilaginous secretion, 
which completely covers the spore (P/. XAT, fig. gr). In optical 
section this envelope appears densely granular at the margin, 
while a clear amorphous area imtervenes between the outer layer 
and the developing plantlet (Pi. XXT, fig. 44). The spore divides 
isto two unequal cells, of which the smaller soon becomes 
slightly pointed and finally grows into the primary root-cell (2. 
: XX, fig. 42). Divisions parallel to the first ensue (Pl. XX, 
igs. 43-45), and the basal-cell elongates so as to form the first 
—— thizoid piercing the mucilaginous sheath, which finally disinte- 
_ Sfatesand disappears. A six-celled stage is often reached before 
divisions in planes at an angle to the first occur. Generally, 
segmentation continues for some time and the siphons are clearly 
marked off from the:central axis before a second rhizoid arises. 
| As in Chondria, this has its origin in an unsegmented cell adja- 
«Cnt to the primary root-cell. The former differs from the 
later only in its brighter color and denser cell-contents; and, 
_ “maining undivided, it forms a component part of the holdfast 
| wae 50). The protoplasmic connections between these 
oe. ate obvious, but they are difficult to trace between the 
= cells of the plantlet (Pl. XXI, figs. 45,47). When three or 
B weeks old the young plant develops several rhizoids spring- 
." the primary or secondary root-cell (Pi. XXT, 
elds Ccasionally, however, the segmentation stage of the 
: a. and the growth of the frond begins before multipli- 
q . rhizoids takes place (Pl. XXII, jig. 10). At the 
’ as .. trond other rhizoids are sent out by corticating cells 
Parated from these by a wall, a protoplasmic connection 
. | = aaa No intracuticular filaments are developed 
’ Noldfast &pendence of the rhizoidal constituents of the ipaietie 
oth Practically preserved (Pi. XXIL, fig. 6). In addition 
¢ thizo; : 
. Zoids near the base of the plant, any corticating cell ofa 
mbent branch 
Bigg; may produce a secondary holdfast and thus 
a m the extensi 
on of the colony. As Strémfelt (8) noted, 
