1899] DEVELOPMENT OF HOLDFASTS OF FLORIDEA 253 
among the cortical cells and medullary hyphe. The root-fila- 
ments have very thick cell-walls and central cells only, these 
being much elongated.” The ends of the rhizoids are swollen 
and in close contact with the cells of the host (seat figs. 4, 5, p. 
256), but no haustoria penetrate the walls of the latter. In one 
imstance a unique variation occurred.’ A few intracuticular fila- 
ments, descending from the corticating cells of the Polysiphonia, 
fan parallel to the main axis of the rhizoid throughout its length. 
The host suffers no serious injury, only a depression and cutini- 
ation of the surface with a very slight disorganization of the 
cortical cells at the point of penetration. Though the associa- 
tion of the two plants does not justify the assumption of com- 
plete parasitism, the symbiotic relation existing between them is 
Much more intimate than that observed between Ascophyllum 
and any of the truly epiphytic alga. According to Brebner (3),a 
‘milar relation exists between Dumontia filiformis and its host, 
serratus. 
Dasya elegans (Martens) C. Ag. was the third species of the 
odomelaceze examined. The spores attach themselves by 
1 * mucilaginous secretion much less definite in form and less 
_ *Petsistent than in Polysiphonia violacea (Pl. XXII, fig. 30). The 
_ ‘Pore elongates before the division takes place, and in many 
F "aa the very young plantlet assumes an hour-glass shape, 
q — with a delicate mucilaginous secretion at either end. 
' a. "o are parallel to one another, forming a long fila- 
: of the Aeg y, of which one terminal cell becomes the apical cell 
= Nd, the other the primary root-cell (Pl. XXL, figs. 31, 
—. Twelve or more parallel divisions may — 
— cell elongates and forms a rhizoid terminating 
 Petiod (PL st such a modification may appear at - earlier 
i. AM, fig. 34). The multicellular disks, which de 
td of : og are like those of Chondria. The root-cell ort e 
4 old broadens and becomes slightly lobed; oblique 
| als eg the lower corners of the cell; division is continued 
ellular disk with a mucilaginous margin results (PI. 
U, 
P3941; XXUL, figs. 2, 3 7,8,9). The primary Toot 
