1896.] The Development of Nemation. 341 
fronds are from one millimeter to about forty centimeters 
in length, and from one to three millimeters in diameter. 
Dichotomous branching is the rule, but irregular branching 
may be found at various points. Branches occur with more 
frequency near the tip of the frond where the gelatinous 
sheath is thinner and where the central filaments can easily 
make their way to the outside. The writer has never found 
new branches arising near the very bases of old fronds. The 
appearance of a tuft of fronds as if all arising from one point, 
which is frequently seen on barnacle shells, is due to the fact 
that the young frond sometimes divides very early in its 
gtowth into several branches, separated by short intervals, 
and the expanded base is common to all these branches. 
n order to study the earliest development of the Nemalion 
Plants, it was necessary to devise some method of cultivating 
the spores. For this purpose shallow dishes were used, upon 
the bottom of which glass slides were placed. A gentle 
‘tteam of sea-water ran constantly into the dishes, and the 
Water was drawn off from the bottom of each dish over the 
edge by asiphon. Fronds possessing mature cystocarps were 
hid over the slides and the spores were shed upon the slides 
m large numbers. Other spores were collected upon slides 
Placed in dishes which were not supplied with running water. 
1 this case the water was very carefully drawn off and re- 
ewed four to five times every day. Spores obtained in this 
Way were watched daily from the Ist until the 12th of ecco 
93. The spores, immediately upon being shed, attache 
themselves to the slides, so that it was possible to keep the 
“ame spores under continuous observation, verifying in indi- 
Viduals i hown in a series of plants. 
snot i from the slides which 
the attached spore is spherical, 
