ALG® OF MID-LITTORAL MARSH a 
SCHIZOMYCETES. 
Of the bacteria only one species is at all prominent in the thallophyte flora 
of the sublittoral belt. This is an undetermined species of Beggiatoa, which 
frequently forms stringy white coatings over the bottoms of the tiny rivulets of 
salt water which run off the marshes or out of the banks of the ditches and 
larger streams. It occurs between the 3-foot and 6-foot levels, always on 
bottom that is continually covered by the trickling water while the tide is low. 
SCHIZOPHYCER. 
Of this group there are 12 species on the Spartina marsh and along the 
streams crossing it. The distribution will be described for each species in 
alphabetical sequence. (For distribution of important species see plate viit.) 
Anabena torulosa: This is the most abundant and widely distributed of all 
the Schizophycese of this mid-littoral belt. Its nearly circular, gelatinous, 
glistening patches are from 1 to 10 cm. in diameter, and are found on the 
firm mud among the Spartina stalks between the 4 and 6 foot levels. The 
patches are very noticeable, as they have the appearance of huge greenish-black 
ink blots on the gray mud. These are chiefly Anabena, but sometimes have 
a small admixture of Lyngbya sp. or of Microcoleus. In other places Anabena 
forms a minor constituent of loose felts over dead leaves of Spartina, which 
consist primarily of Lyngbya, Microcoleus, and Oscillatoria. Anabena is 
apparently a summer denizen of this belt. Its striking dark-green, gelatinous 
blots were entirely absent from their usual habitat in both April and September 
of 1911. The lowest level at which Anabena has been found is 4 feet. The 
highest patches were seen among the stalks of Scirpus americanus at the 7-foot 
level. This alga seems to be most frequent near the fresh-water streams. For 
example, it is found along the edge of the large marsh south of the harbor 
and along the west shore, which, as we have seen, abounds in fresh rivulets and 
springs. It has not been found forming pure growths on the south shore of the 
Spit, where fresh water is wanting. 
Chroococcus turgidus was found only occasionally, and then it was on erect 
stubble of Spartina glabra near the 6.33-foot level. 
Isactis plana is a rather frequent constituent of the felts on the Marsh, 
being usually mingled with the Lyngbyas, Vaucherwas, etc. (300 south by 625 
east at 6 feet). 
Lyngbya estuaru, L. semiplena, and two or three unidentified species are of 
frequent occurrence in the present zone, between the 4-foot and 6.5-foot levels. 
Most, if not all, of these are also found above the limits of this belt. These 
species, when found in the present belt, usually grow on the mud about the 
bases of the Spartina, and form parts of mats or tangles, in which species of 
Rhizoclonium and its allies Chetomorpha and Cladophora are the chief con- 
stituents. This mixture is found very generally about the harbor, where 
there is sufficient light for the alge between the Spartina stalks. It is 
especially frequent along the borders of the little rivulets of brackish fresh 
water that run across this belt from the upper beach. It is also seen among the 
Spartina where the latter is more scattered, at the upper margin of this mid- 
littoral belt. These same Lyngbyas are also found mixed rather sparsely with 
Anabena near the 4 and 5-foot tide-levels. 
