ALG OF UPPER LITTORAL BELT 93 
THE SCHIZOPHYCER. 
To this class belong two-thirds of all the algee appearing in this belt, as may 
be seen from the two lists on page 90. 
Amphithriz is found on stones in fresh-water rivulets near the lower limits 
of the present belt, as at 1,000 north on the east side. 
Anabena torulosa Lagerh. (Spherogyza carmicheli of Farlow 1881) is, as we 
have seen, more abundant and widespread in the mid-littoral belt. Its 
blackish-green circular patches, however, are not infrequently found between 
the 6.5 and 7 foot levels, especially on mud beside fresh-water rivulets, occupied 
chiefly by Scirpus americanus (e. g., 1,240 north by 575 west). 
Anabena variabilis is a second species that has been found among felted 
threads of Lyngbya at the 7-foot level, e. g., at 1,720 north on the west side. 
Calothriz crustacea is usually the most important constituent of the denser 
felts and incrustations of alge which occur on the south shore of the Spit, espe- 
cially between 560 and 670 west, and 150 and 580 east. These felts are usually 
found at one or two points each on the east and west shores, e. g., 950 north by 
970 east. The most abundant associates of this Calothria in these felts are 
Lyngbya semiplena, Microcoleus chthonoplastes, Rhizoclonium, and Vaucheria. 
The Calothriz is found most frequently between the 6.5 and 7.5 foot levels, and 
on the compact, rather moist soil of a footpath along the Spit, where it is 
partially shaded by seed plants. It is not found near the fresh-water rivulets. 
Calothrix fusco violacea occurs on the stones of wharves, on the Marsh, and 
on soil and pebbles on both the east and west sides of the harbor at 6.5 to 7.5 
feet (950 north by 975 east; 1,060 north by 450 west). It forms dark greenish 
patches of several square centimeters in extent. 
Calothria pulvinata is a species that forms honey-comb-like spongy coats of 
2 to 3 mm. thickness over sandy soil (950 north by 975 east), or on piles and 
logs of wharves (2,300 north by 1,300 east; 1,060 north by 450 west). It is 
found at higher levels than the other species of Calothriz, being recorded only 
from between the 7 and 8 foot levels. 
Calothriz scopulorum is a fourth species of this genus, and is less abundant 
than C. crustacea. It occurs as a dense black felt, nearly a millimeter thick, on 
pebbles or very compact soil. 
Lamprocystis roseopersicina (Cohn) occurs in a few warm tide-pools on the 
Marsh, e. g., at 0 south by 1,005 east at 7.33 feet. It forms a thin, light purplish 
coating over the soft mud, pebbles, or decaying plants in the bottom of the pool. 
It was found only in places where it would be constantly covered, or at least on 
substrata that are constantly saturated with salt or brackish water. In April 
1911 very little of the Lamprocystis was found, and this was confined to narrow 
bands about the lateral surfaces of pebbles just above the surface of the mud in 
which they were partially embedded. 
Isactis plana is occasionally found in this belt, forming close felts or incrusta- 
tions over the mud or pebbles, very similar to the more abundant ones of 
Calothriz. 
The genus Lyngbya is represented in this zone by L. estuarit, L. lutea, L. 
semtplena, and three or four other less abundant species, which have not been 
identified. Of these, L. estuarit, the occurrence of which at lower levels we have 
noted, is the most important because of its more general distribution and its 
abundance. About the borders of the Marsh south of the harbor, L. estuart is 
