458 BULLETIN OF THE BUREAU OP FISHERIES. 



uncialis grows on rocks above and below low-water mark and is conspicuous in the 

 winter and spring. C. refracta and C. Rudolphiana are frequently abundant on stones 

 near low water and below. C. rupestris is a striking species growing off exposed points 

 as at Nobska and Gay Head. 



The list of Cladophoras in this region is large, but they are apt to grow mixed with 

 other algae. However, C. albida, C. albida var. refracta, C. arcta, C. gracilis, and C. 

 lanosa var. uncialis frequently form extensive and almost pure growths, which are as 

 conspicuous as the zones of Ulva, Enter omorpha, and Monostroma. 



(io) THE VAUCHERIA ASSOCIATIONS. 



Vaucheria lilorea and V. Thuretii are occasionally found forming rather extensive 

 and sometimes matted growths over gravel and mud near low-water mark and below. 



(il) THE ECTOCARPUS ASSOCIATIONS. 



Most of the species of Ectocarpus grow attached to larger algae or to Zostera, but 

 some are found on stones and the woodwork of wharves near low-water mark and below. 

 Ectocarpus confervoides and E. siliculosus are frequently present in the latter situations, 

 forming at times extensive growths. Some of the epiphytic species may grow so thickly 

 over such forms as Scytosiphon lomentarius , Desmarestia aculeata, Chordaria flagelli- 

 formis, Chorda filum, Laminaria Agardhii, and Zostera as to form a conspicuous part 

 of the associations that contain these larger algae and the eel grass. The commonest 

 of the epiphytic species are Ectocarpus cecidioides on old Laminaria, E. confervoides on 

 Scytosiphon and Chordaria, E. fasiculatus on Chordaria and Chorda, E. granulosus on Sar- 

 gassum, E. penicillatus on larger algae and Zostera, and E. siliculosus on Scytosiphon, 

 Zostera, etc. 



(12) THE CLADOSTEPHUS ASSOCIATION. 



Cladostephus verticillatus grows in fairly deep water and has a scattered distri- 

 bution in Vineyard Sound (chart 229). It was dredged in 2 to 13 fathoms over sandy 

 and stony bottoms. Although not plentiful, this species is conspicuous for its size; it 

 is a member of the warm- water sublittoral formation (b) . 



(13) THE SPHACELARIA ASSOCIATIONS. 



Sphacelaria cirrhosa is epiphytic on Fucus, Ascophyllum, Sargassum, and occasion- 

 ally on Zostera; it may also grow on stones. The species is probably widely distributed 

 along the coast and was dredged in 3 to 8 fathoms on Sargassum and stones at several 

 scattered stations in Vineyard Sound. 



Sphacelaria radicans is common attached to stones, shells, and mud-covered rocks. 

 It was dredged in 3 to 5 fathoms, chiefly at stations near Vineyard Haven. 



The two species are in the warm-water sublittoral formation (b). 



(14) THE DESMOTRICHUM AND PUNCTARIA ASSOCIATIONS. 



Desmotrichum balticum and D. undulatum are common, especially in the spring, 

 forming dense growths on Zostera; they are occasionally found on larger algae and on 

 rocks. 



Punctaria latifolia and P. plantaginea are likewise common in the spring, the former 

 on Zostera and larger algae, the latter on algae and rocks. 



