BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 
*Cladophora gracilis and occa- 
sionally other species. 
Ascocyclus orbicularis (0). 
*Ectocarpus confervoides. 
E. penicillatus. 
*E. siliculosus. 
Sphacelaria cirrhosa (0). 
*Desmotrichum balticum (in the 
spring). 
*P. undulatum (in the spring), 
Pogotrichum filiforme (0). 
*Punctaria latifolia. 
Rhadinocladia Farlowii (0). 
Giraudia sphacelarioides (0). 
Castagnea virescens (0). 
Hecatonema maculans (0). 
Myrionema vulgare. 
Stilophora rhiz»des (0). 
Erythrotrichia ceramicola. 
*Porphyra leucosticta (in the 
spring). 
Chantransia secundata. 
*C. virgatula. 
Antithamnion cruciatum (in 
deep water). 
Callithamnion Baileyi. 
C. Baileyi var. laxum. 
*C. byssoideum. 
*C. corymbosum. 
*C. roseum. 
C. rubrum. 
*C. strictum. 
*C. tenuissimum. 
*Seirospora Griffithsiana. 
*Spyridia filamentosa (0). 
Chondria dasyphylla (o). 
Chondria sedifolia (0). 
*Dasya elegans. 
*Polysiphonia Harveyi. 
*P. Olneyi. 
P. variegata (0). 
Rhododermis Georgii (0). 
Melobesia farinosa. 
*M. Lejolisii. 
*C. Zostere. *Ceramium fastigiatum. 
The Zostera formation endures temperatures considerably higher than those given 
for the range of the warm-water sublittoral, especially where the eel grass grows in 
coves or other sheltered stations. Such waters may remain above 70° F. for many 
days, probably at times reaching as high as 75° to 78°. These conditions as to heat 
are the most extreme of any in this region, except of course the small brackish pools 
and ditches of the salt marshes. 
A WINTER SUBLITTORAL FORMATION. 
It is clear that, as the temperature of the Bay and Sound falls during the autumn, 
the conditions become less favorable for the warm-water sublittoral flora. Many species 
characteristic of waters south of Cape Cod pass out of season, although certain species 
which may be said to endure the summer’s heat are at their best in the winter season. 
A cold-water winter sublittoral formation is thus developed, which extends throughout 
the Bay and Sound, reaching its best development probably in the late winter and early 
spring. 
We know nothing of this winter and spring flora in the deeper waters’ of the Bay 
and Sound, for there have been no dredgings for alge at these seasons. The cool-water sub- 
littoral formation of the lower portion of the Bay and westerly portion of the Sound would 
be expected to enter the more sheltered regions occupied by the warm-water sublittoral 
during the summer, but how far it may extend is a matter of conjecture. Undoubtedly 
species appear which are not present in either Bay or Sound during the summer, some 
probably developing from resting spores that carry the forms through the summer, and 
others coming in by means of spores ‘brought from a distance. 
It is probable that numbers of northern species, the spores of which might be brought 
from a distance, would be able to establish themselves, develop to maturity, and perhaps 
pass through several generations before the temperature rises sufficiently in the spring 
to put an end to their growth. Species of Cladophora, Ectocarpus, and other rapidly 
growing green and brown alge, reproducing by zoospores, are admirably fitted for a 
periodical winter invasion, and some of the smaller red alge which mature quickly 
would also be expected to take part in such a migration. 
Some observations on the algal vegetation along shore in shallow water have been 
made during the winter and spring, and if these are indices of the general change through- 
