J oknson— Observations on Phaeozoosporeae . 143 
to the superficial cortical cells, but are formed also from any 
joint-cell of the primary cellular axis (Fig. 12), and from any 
joint-cell of the hair-pinnules (Fig. 14). Hence, morphologically, 
any cell of the thallus is capable of becoming a sporangium. 
Each sporangium contains one spore only, occasionally two 
to four. Each spore is of large size, much larger than the 
ordinary phaeophycean zoospore, and more like the spore of 
Pylaiella fulvescens , or of P. litoralis , or of the Tilopterideae. 
Whether the spore is ciliated, like the ovum of Cutleria , or 
non-ciliated, like that of Tilopteris , whether it is an ovum, or 
comparable to the tetrasporangium-like body in Tilopteris , I 
cannot say. It will be seen that, though my observations on 
the sporangia have, unfortunately, not gone far, they yet 
throw some light on the relationship of Desmarestia to the 
Tilopterideae. Careful microscopic examination of Desma- 
restia, at all seasons of the year, would yield results of great 
interest. 
Summary. 
1. In Carpomitra Cabrerae Kiitz., and Sporochnus peduncu - 
latns A g., the mode of growth of thallus is trichothallic, the 
apices of the branches being occupied by tufts of innumerable 
radiating hairs with basal growth. The mode of growth is 
readily derivable from that in Ectocarpus . The sporangia are 
unilocular, multisporous. The terminal cell of each paraphysis 
is assimilative, not reproductive. The receptacle is the modi- 
fied apex of a thailus-branch, and is, in S. pedunculatus , some- 
times branched. The zoospores of 5. peduncidatus are sensitive 
to light, and apparently capable of independent germination. 
2. In Asperococcus Lamour, plantlets arise on the thallus 
by trichothallic germination, from hairs with basal growth, 
much as in Punctaria Grev., to which Asperococcus is much 
more closely related than is at present admitted. 
3. In Arthrocladia villosa , (Huds.) Duby, the sporangia are 
unilocular, multisporous, and form stalked chain-like sori. 
The zoospores after their escape behave like those of 6'. 
pedunculatus . 
