466 BULLETIN OF THE BUREAU OF FISHERIES. 



throughout the Bay and Sound (chart 251), but is most abundant off exposed situations, 

 as at Gay Head and Cuttyhunk, where extensive growths are present. 



Phyllophora membranifolia is also found on stones and over sand and mud; it was 

 dredged in 3 to 17 fathoms (most plentiful in 4 to 10 fathoms). The species is likewise 

 distributed very generally throughout the Bay and Sound (chart 252), but appears to 

 prefer rather more sheltered situations than Phyllophora Brodicei. 



Both species of Phyllophora are prominent in the cool- as well as the warm-water 

 subUttoral formations. 



(46) THE AGARDHIELLA ASSOCIATION. 



Agardkiella ienera is very common on stones and shells in fairly deep water; it 

 grows in 2 to 15 fathoms (most plentiful in 4 to 10 fathoms). The species is very widely 

 distributed throughout both the Bay and Sound (chart 253), but prefers rather sheltered 

 waters and is a characteristic member of the warm-water sublittoral formation (b), 

 where it is commonly associated with Grinnellia americana. 



(47) THE CYSTOCLONIUM ASSOCIATIONS. 



Cystoclonium purpurascens has a scattered distribution in both Bay and Sound 

 (chart 254). It was found in 2)4 to 13 fathoms (most plentiful in 4 to 10 fathoms) 

 attached to stones over sandy, shelly, and stony bottoms, occasionally over mud. The 

 species rarely forms extensive patches but is conspicuous because of its large size; it 

 is found in both the cool- and warm-water sublittoral formations. 



Cystoclonium purptirascens var. cirrhosuni is abundant in the lower portion of the 

 Bay and westerly portion of the Sound (chart 255). It was dredged in i to 17 fathoms 

 (most plentiful in 4 to 12 fathoms) attached to stones and to larger algae over a bottom 

 similar to that of the preceding species. The variety is much more luxuriant than the 

 species and frequently forms large patches of vegetation; it clearly prefers the condi- 

 tions of the cool -water sublittoral and is a prominent member of that formation (a). 



(48) THE CHAMPIA association. 



Champia parvula is one of the most widely distributed algae of the region, occa- 

 sionally forming extensive patches in the Bay and Sound (chart 256). It grows in i to 19 

 fathoms (most plentiful in 4 to 12 fathoms) attached to stones, Zosicra, and larger 

 algae, over sandy, shelly, stony, and muddy bottoms; it is frequently found in shallow 

 water along the shore. The species belongs to the warm-water sublittoral formation 

 (b) , being found most abundantly in sheltered regions. 



(49) THE LOMENTARIA ASSOCI.\TIONS. 



Lomentaria rosea is found only off the exposed points of Gay Head and Cuttyhunk 

 (chart 257). It was dredged in 4 to 13 fathoms on stones, shells, and on larger algae, over 

 sandy, shelly, and stony bottoms. The species is restricted to the cool-water sublittoral 

 and although never abundant is one of the most characteristic members of this forma- 

 tion (a). 



Lomentaria uncinaia grows in the sheltered waters of the Bay and Sound (chart 258). 

 It was dredged in i}{ to 15 fathoms (most plentiful in 4 to 10 fathoms) over sandy, 



