LITHOPHILOUS BENTHOS Lak 
2,000 north by 200 to 400 west. The same is true even if the water moisten- 
ing the plants at low tide is fresh water, e. g., at 1,300 to 1,600 north by 1,000 to 
1,075 east, or near the mouth of the creek at 200 north by 400 to 600 east. 
B. ATTACHED ALGAD OF THE HARBOR BOTTOM (THE “ LITHOPHILOUS 
BENTHOS ”). 
Under this head we include alge attached to stones, shells, or stakes below 
the 1.5-foot level, the “ Lithophilous Benthos” of Warming. Many specimens 
of these same species may be broken off and found drifting about the harbor 
entirely free of any support. Though 18 or 20 species of algee may be found on 
the bottom of the harbor, only 7 or 8 of these, including the Ulva and Entero- 
morpha clathrata mentioned above, occur in any considerable numbers. Even 
these are not at all abundant except in the Inlet, or, in the case of three or four 
species, along the streams entering the harbor. 
The species that have been found on the bottom at one time or another are: 
Beggiatoa mirabilis, Oscillatorva sp?, Cladophora (expansa?), Enteromorpha 
clathrata, HE. intestinalis, Ulva lactuca, Ascophyllum nodosum, Hctocarpus 
stliculosus var. amphibius Harv., Fucus vesiculosus, Pylaella littoralis, Scyto- 
siphon lomentarius, Agardhiella tenera, Callithamnion roseum, Ceramium 
rubrum, Chondria tenuissima, Chondrus crispus, Dasya elegans, Delesseria 
leprieuru, Gracilaria multipartita, Grinnellia americana, Hildenbrandia 
prototypus Nardo, Petrocelis cruenta, Polysiphoma variegata, Porphyra 
lacimata. 
In discussing the occurrence of these alge we may take up in some detail 
the distribution of the more abundant species in each class, and then note 
briefly the information that we have been able to gather concerning the 
occurrence of the rarer or occasional forms. 
SCHIZOPHYTA. 
Beggiatoa mirabilis occurs commonly on the surface of the black mud of the 
bottom, from below mean low water up into the present belt, and also, as we 
shall see, still further up, to the 6 or 7 foot level, in tide-pools, or in trickles 
of salt water at the edge of the estuarial marsh. Osctllatoria sp? was found 
only infrequently coating the surface of dead fronds of Fucus in the Inlet, at 
about mean low water. 
CHLOROPHYCE. 
Of the green algee enumerated above we have already noted the distribution 
of attached plants of Enteromorpha clathrata (p. 21) and Ulva (p.18). The 
only remaining species are Cladophora (expansa?), Enteromorpha intestinalis, 
and Ulothrix flacca. 
In April 1911 tufts of Cladophora (expansa?) 3 or 4 cm. long were found 
frequently along the Inlet near mean low water at 1,800 to 2,000 north. In 
September 1911 similar tufts were frequent in the creek, at 200 south, between 
the 1 and 2 foot levels. Considerable mats of it are found each summer tangled 
with Zostera and with other alge in the middle of the harbor bottom, where 
it also occasionally appears as an epiphyte on Zostera (plate vir). At this 
season it is much more abundant at higher levels, as we shall see later. 
