474 BULLETIN OF THE BUREAU OF FISHERIES. 
out the sublittoral, the flora of the bottom of the Bay and Sound must be very different 
indeed from that of the summer. Especially interesting are the series of studies of 
the flora of Spindle Rocks, Woods Hole, which were made at intervals throughout a 12- 
month cycle in 1904 and 1905. These are described in the next section of this paper. 
Such intensive studies over long periods of time are very much to be desired to determine 
the seasonal changes in algal floras. 
We give below a list of the alge so far known to be present in the cold-water 
sublittoral formation of the winter and spring: 
Monostroma Grevillei. Desmotrichum balticum. P. leucosticta. 
Ulva Lactuca. D. undulatum. Chantransia secundata. 
Chetomorpha Linum. Pogotrichum filiforme. C. virgatula. 
Cladophora arcta. Punctaria latifolia. Antithamnion americanum. 
C. lanosa. P. plantaginea. Callithamnion Baileyi. 
C. lanosa var. uncialis. Desmarestia viridis. Ceramium rubrum. 
Derbesia vaucherizformis. Dictyosiphon foeniculaceus. Polysiphonia fastigiata. 
Ectocarpus ecidioides. Giraudia sphacelarioides. P. nigrescens. 
E. confervoides. Castagnea virescens. P. urceolata. 
E. elegans. Chordaria flagelliformis. Rhodomela Rochei. 
E. fasciculatus. Hecatonema maculans. R. subfusca. 
E. granulosus. Myrionema corunne. Ahnfeldtia plicata. 
E. ovatus. M. vulgare. Chondrus crispus. 
E. penicillatus. Chorda tomentosa. Sterrocolax decipiens. 
E. siliculosus. Laminaria Agardhii. Rhodymenia palmata. 
E. tomentosus. Haplospora globosa. Gloiosiphonia capillaris. 
Pylaiella littoralis. Scaphospora Kingii. Rhododermis Georgii. 
Sorocarpus uveeformis. Erythrotrichia ceramicola. 
Asperococcus echinatus. Porphyra laciniata. 
The cold-water sublittoral formation accepts a winter temperature, which for at 
least two and a half months probably averages under 35° F., as indicated by the records for 
Great Harbor, Woods Hole (the average temperature between December 25 and March 
15 for the years 1902-1906 was below 35°). Many of the species of this formation reach 
their best vegetative condition and fruit during the spring, and then pass out of season. 
During this period the temperature of the water rises steadily, passing 60° about June r. 
THE LITTORAL FORMATIONS. 
As has been stated before, the algal growths in the littoral region are not very 
striking in the immediate vicinity of Woods Hole, chiefly for these reasons, (1) that the 
tides are small, (2) that the shore line is very broken, (3) a marked boreal flora is 
absent, and (4) the scraping of floating ice in the winter prevents the development of 
an extensive littoral flora at this season. Neighboring coasts exposed sufficiently as to 
be free from floating ice, as at Cuttyhunk, have heavy growths of alge in the winter, but 
there have been no opportunities for thorough studies at this season. These growths 
are, however, undoubtedly composed largely of rockweeds (Fucus and Ascophyllum). 
The littoral formations of the different seasons at Woods Hole are of a very spotted 
character, rarely being so extensive as to attract attention and generally breaking up at 
once into small associations. Of these the following are at times very evident: The 
Calothrix associations (3), the Rivularia associations (4), the Plewrocapsa association 
