BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 479 
prominent zone (much more conspicuous than in chart 271) was just below low water and 
composed of Ceramium rubrum (43) and Polysiphonia violacea (48), these two forms 
having taken the region formerly occupied by the brown zone. Chart 273, recorded Sep- 
tember 19, 1904, a year previous to the last, is interesting because there was no Chordaria 
flagelliformis that season and very little Polysiphonia violacea, but an abundance of 
Polysiphonia fibrillosa (46), which took the place of the first two species, forming with 
Ceramium rubrum (43) a dense zone below low-water mark. 
The conditions at the beginning of the winter and before the rocks were scraped 
by floating ice are shown in chart 274, recorded December 30, 1904. This chart in the 
sequence follows chart 273, of September 19, 1904, and precedes chart 267, of March 17, 
1905, by two and one-half months. The prevailing green alga was Cladophora lanosa 
» var. uncialis (11), which had taken the place of Ulva Lactuca var. rigida (5), so abundant 
in the summer, but now only represented by the bases of old plants. The brown zone 
was composed of Phyllitis fascia (24) and Scytosiphon lomentarius (26); there was no 
Chordaria flagellijormis. Ceramium rubrum (43) was abundant below the brown zone 
but Polystphonia fibrillosa (46) had almost disappeared. Two species of Ectocarpus were 
present, together with several other epiphytic brown and red alge. 
A close study of this series of charts will show very graphically the general nature 
and extent of the seasonal changes that must take place on very many ledges and groups 
of rocks along the coast, and similar seasonal changes would be expected wherever there 
is a well-developed littoral and sublittoral flora near low-water mark. Intensive studies 
of this character of well-chosen situations are far more important for our knowledge of 
seasonal habits and algal successions than random collecting undertaken along the shore. 
It is much to be desired that such work be systematically undertaken by those in a 
position to make detailed records over extended periods. Perhaps this brief record of a 
study (abruptly terminated by the destruction of the selected station), which shows 
such interesting results, will lead others to make similar investigations. 
In conclusion we wish to acknowledge our indebtedness to Miss Lillian J. MacRae, 
who, with the assistance of Mr. Collins, made the records of several charts at seasons 
when it was impossible for us to be at Woods Hole. 
