BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 465 



ber of the cool-water sublittoral formation ; it was dredged in the summer in the lower 

 portion of Buzzards Bay in 2 to 19 fathoms. 



Polysiphonia variegata is common in the summer on stones, Zostera, and larger 

 algae, and also grows loosely attached over sand and mud in sheltered situations; it 

 was dredged in 3 to 6 fathoms in the upper portion of Buzzards Bay (chart 248). The 

 species belongs to the warm-water sublittoral formation, preferring sheltered situations. 



Polysiphonia violacea is abundant in the summer on stones, rocks, and on the larger 

 algae below low-water mark; it was dredged in i to 13 fathoms over sandy and stony 

 bottoms and has a wide though scattered distribution in the Bay and Sound. The 

 species is an important member of the zone of red algae below low-water mark on rocks 

 in exposed situations, taking the place which P. urceolata occupies in the spring. It 

 belongs to the warm-water sublittoral formation. 



(42) THE RHODOMELA ASSOCIATIONS. 



Rhodomela Rochei and R. subfusca are probably very abundant in the spring through- 

 out the Bay and Sound. The bases of old plants were dredged during the summer 

 at scattered stations in 3 to 8 fathoms for Rhodomela Rochei, and 3 to 12 fathoms for 

 R. subfusca. In the spring these species are undoubtedly conspicuous members of 

 the cool-water sublittoral formation (a). 



(43) THE AHNFELDTIA ASSOCIATION. 



Ahnfeldtia plicata is common in exposed situations as off Gay Head and Cutty- 

 hunk (chart 249). It was dredged in i to 14 fathoms (most plentiful in 7 to 13 

 fathoms) over sandy, shelly, and stony bottoms, and is one of the cool-water subUttoral 

 species. 



(44) THE CHONDRUS ASSOCIATION. 



Chondms crispus, the Irish moss, is abundant along the shores of the Bay and 

 Sound below low- water mark; it was dredged in i to 19 fathoms (most plentiful in 

 4 to 12 fathoms) over sandy, shelly, and stony bottoms. The species is widely dis- 

 tributed through the Bay and Sound (chart 250), wherever the bottom is favorable, 

 and grows in dense patches on the rocks. It does not as a rule come so close to the 

 surface as Ceramiuni rubrum, Polysiphonia fibrillosa, P. urceolata, and P. violacea, 

 but it is the most conspicuous member on exposed rocks of the zone of red algse some- 

 what below these species. Chondrus crispus is a very important member of both 

 the cool and warm-water sublittoral formations, with preferences for the former; for, 

 although enduring the warm water of the summer, it grows most luxuriantly in colder 

 temperatures. 



(45) THE PHYLLOPHORA ASSOCIATIONS. 



The two species of Phyllophora have very similar life habits ; they are rarely found 

 in the upper level of the sublittoral region and are generally present only at a considerable 

 depth. 



Phyllophora Brodicei grows on stones and in sand and mud and was dredged in 

 iK to 15 fathoms (most plentiful in 4 to 10 fathoms). It is distributed very generally 

 16269° — Bull. 31, pt I — 13 ^30 



