468 BULLETIN OF THE BUREAU OF FISHERIES. 



(55) THE HILDENBRANDIA ASSOCIATION. 



Hilderibrandia prototypus is common on stones and rocks near low-water mark and 

 extending into deep water, where it grows in i}4 to 14 fathoms (most plentiful in 4 to 

 10 fathoms) ; it is widely distributed in the Bay and Sound (chart 264). The species is 

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



(56) THE LITHOTHAMNION ASSOCIATION. 



Liihothamnion polymorphum grows on stones and shells in fairly deep water and is 

 rather widely distributed in the Bay and Sound (chart 265). It was dredged in 2 to 15 

 fathoms (most plentiful in 4 to 10 fathoms) over sandy, shelly, and stony bottoms. 

 Lithothamnion, although never found in abundance, is present in both the cool- and 

 warm-water sublittoral formations. 



(57) THE MELOBESIA ASSOCIATIONS. 



Melobesia farinosa is fairly common on Fucus vesiculosus, Chondrus, Phyllophora, and 

 Zoster a at low- water mark and below, being dredged in $% to n>£ fathoms, at scattered 

 stations in the Sound. The species is a member of the warm-water sublittoral formation. 



Melobesia Lejolisii is very abundant on Zostera throughout the Bay and Sound in 

 both shallow and deep water; it was dredged in 2 to 12 X fathoms. The species prefers 

 rather sheltered waters, where it may cover the eel grass with a thin incrustation ; it is 

 characteristic of the Zostera formation. 



Melobesia membranacea is occasionally found on Chondrus and Phyllophora, generally 

 in exposed situations as off Gay Head, Cuttyhunk, and Penikese. It was dredged in 

 2,% to 10 fathoms and clearly belongs to the cool- water sublittoral formation. 



Melobesia pustulata is common on Ascophyllum, Chondrus, and Phyllophora, and is 

 present in both shallow and deep water, being dredged in 1% to 14 fathoms off Gay 

 Head, Cuttyhunk, and in the easterly portion of the Sound. The species has a scattered 

 and probably rather general distribution along the shore, and is a member of both the 

 cool- and warm-water sublittoral formations. 



THE COOL-WATER SUBLITTORAL FORMATION. 



The cool-water sublittoral formation of the summer contains a number of very 

 interesting and characteristic algae, some of which are limited in their distribution to the 

 exposed waters off Gay Head and the reefs of Sow and Pigs. Other species have a more 

 extended range throughout the lower portion of Buzzards Bay and the westerly portion 

 of Vineyard Sound. Finally there is a group of species which, while most abundant in 

 the regions described above, are also found in other portions of the Bay and Sound, where 

 they form a part of the sublittoral flora characteristic of these more sheltered, and in 

 the summer, warmer waters. 



The species in these lists preceded by an asterisk (*) are the larger or more abundant 

 forms which dominate the formation ; species which are rare or occasional are followed 

 by an (o). 



The most interesting and noteworthy species in this formation are those which are 

 especially characteristic of the cold waters north of Cape Cod and have been recorded only 



