EPIPHYTIC ALGH ON ZOSTERA, ETC. Sys) 
Melosira borres and M. nummuloides: These diatoms, though less abundant, 
are even more widely distributed over the harbor-bottom than Cocconets, since 
they endure submergence, for several hours at least, in entirely fresh water. 
They are best developed, however, on the long leaves of Zostera or on stakes or 
buoys in the middle of the harbor. Here they form tufts of a rusty brown 
color from 2 or 3 to 25 or 30 mm. in diameter and from 4 or 5 to 25 or 30 mm. 
in length. The distribution of these tufts is somewhat more restricted than 
that of Zostera. They are present in considerable numbers only on the larger, 
denser Zostera near the center of the harbor. On outlying Zostera, as well as 
on Ulva, Enteromorpha, Pylaiella, and on several of the Floridexe of the 
bottom, Meloswra is found in single threads or clusters of few short filaments. 
Apparently all these Melosira tufts of the bottom and those along the Creek 
to 200 south are of the same species and are identical with those which occur 
mixed with Cyanophycese and Chlorophycee on marsh and beach at higher 
levels. The distribution of Melosira tufts is limited primarily by that of the 
plants on which it grows. It is evident, however, that though Melosira does not 
grow in the swiftest currents, it is most luxuriant where there is a considerable 
movement of the water, e. g., at the sides of the deeper channel leading from the 
Inlet toward the Creek and near the tide-stream entering the deep hole from 
the northwest. The abundance of Melosira on the Zostera, just aside from the 
swiftest current, where the Inlet opens into the Outer Harbor, confirms the 
conclusion that frequent change of the surrounding water is distinctly advan- 
tageous for this diatom. 
Navicula grevillei and N. kennedyi: These species have much the same dis- 
tribution as Melosira in the middle of the harbor, and are even more abundant 
and more luxuriant than Melosvra on the denser Zostera. The tufts of these 
Naviculas are distinguishable from those of Melosira by the somewhat lighter 
color, the slippery feel, and the abundant branching, as well as by the iridescent 
character of the gelatinous matrix in which the frustules are embedded. 
Synedra affinis: 'This is another diatom which is widely distributed on many 
hosts. It was especially abundant on Pylaiella in the Inlet on April 8, 1911, 
and on Pylatella and Enteromorpha intestinalis, in the Creek at 200 south in 
September 1911. On many branches of the Pylavella these diatoms stand out so 
thickly as to make these branches look lke diminutive chenille cords. 
There are of course other epiphytic diatoms (see list on p. 161), but those 
mentioned are the most abundant and widespread in distribution. 
CHLOROPHYCE. 
The only important epiphytic Chlorophycee are Chetomorpha erea forma 
linum, Cladophora (expansa?), and Enteromorpha clathrata. 
Chetomorpha erea: Though this is originally epiphytic, it is found most 
frequently lying on the Ulva or tangled with Zostera, Cladophora, or Entero- 
morpha on the bottom, near the middle of the harbor. What is apparently the 
same species is found at higher levels among the Spartina glabra. 
Cladophora (expansa?): This is a species which is rather frequent in little 
tufts attached to Zostera near the deep hole, though far less abundant than its 
fellow-epiphytes Hnteromorpha clathrata and the two Ceramwms. The tufts 
of Cladophora are 2 or 3 cm. long and are made up of repeatedly branched and. 
densely interwoven filaments. 
