484 



BULLETIN OF THE BUREAU OF FISHERIES. 



no algal life. The most important of these were around the following groups of stations : 

 (7677. 7592); (7708, 7709, 7590); (7679. 7681, 7702); (7577.7597.7682, 7698, 7699, 

 7700, 7727); (7573, 7574, 7695); (7569. 7570, 7736). 



Proceeding eastward into the Sound from the entrance the most marked change in 

 the algal life is the appearance of such species as Arthrocladia villosa, Chorda filum, 

 Dictyosiphon hippuroides, Agardhiella ienera, Ceramium tenuis simum, Champia parvula, 

 and Grinnellia americana. These were not found in the deeper waters at the entrance of 

 the Sound, but were all fairly abundant eastward, Agardhiella, Champia, and Grinnellia 

 being very characteristic of the Sound flora from this point on. 



The most striking feature of the summer flora in the deeper waters at the entrance of 

 Vineyard Sound is the presence in considerable quantity of certain species restricted 

 wholly or almost wholly to the more open waters included in the survey. Prominent 

 among these are Laminaria Agardhii var. viitata, Laminaria digitaia, Delesseria sinuosa, 

 Lomentaria rosea, Plumaria elcgans, and Rhodymcnia palmata. Considered as a whole, 

 the flora at the westerly entrance of Vineyard Sound takes its chief interest from the 

 presence of species peculiar to the cool -water sublittoral formation. 



The narrow portion of Vineyard Sound will now be described. This lies between 

 the islands of Naushon and Marthas Vineyard and may be included between a line 

 drawn from Kopeecan Point to the west end of Naushon (Robinsons Hole) and a line 

 from West Chop to Nobska Point. The bottom is much more varied (see chart 227) 

 than in the westerly portion of the Sound, which in the deeper waters is almost entirely 

 hard sand. There are, however, some extensive areas of sand adjacent to similar 

 regions in the westerly portion of the Sound, and the region between the Middle Ground 

 and Marthas Vineyard is likewise sandy. A few stations (7554, 7564, and 7697) pre- 

 sented a muddy bottom. All other stations comprising the greater part of the middle 

 region of this portion of the Sound showed a bottom of gravel or gravel and stones. 

 The general character of the bottom may be described as variegated, areas of gravel 

 lying next to areas of sand or of large pebbles, the distribution of the sand being deter- 

 mined in all probability largely by the varied flow and scouring of the tidal currents. 

 The greatest depths were from 15 to 17 fathoms; the average depth about 10 fathoms. 



The following algae were found in the deeper waters of this, the narrowest portion 

 of the Sound: 



Arthrocladia villosa, 7733 many; 39 and 7732, few. 

 Chorda filum, 7542bis, 7551, 7557, and 7559, few. 

 Chordaria flagelliformis, 7524 and 7525, few. 

 Cladostephus verticillatus, 7525bis, 7744. and 7753, 



few. 

 Desmarestia aculeata, 7739, few. 

 Desmarestia viridis, 7525bis, many; 7522bis, 



7524bis, 7543bis, and 7549 (1907), few. 

 Ectocarpus siliculosis, 752sbis, few. 

 Laminaria Agardhii', 7525bis, many; 7524bis, 



7532bis, 7533bis, 7536, 7541, 7557, 7732, 7739, 



7740, and 7749, few. 

 Mesogloia divaricata, 7548, few. 

 Ralfsia clavata, 7524bis, few. 

 Sargassum Filipendula, 7525^3, 7533bis, 7537, 



7551. 7SS4. 7555. 7557. 774o, 7742. 7744, 7749, 



and 7750, few. 



Actinococcus subcutaneus, 752ibis and 7525bis, 



many; 7522bis and 7S25bis, few. 

 Agardhiella tenera, 7525bis, many; 7533, 7S33bis 



7535. 7536. 7537. 7540, 7541, 7S4ibis, 7542, 



7S43bis, 7553, 7559, 7562, 7733, 7744, 77SI, 7753, 



and 7754, few. 

 Ahnfeldtia plicata, 7524bis and 7S25bis, few. 

 Antithamnion cruciatum, 7543bis and 7554bis, 



many; 752ibis, 7522bis, 7S23bis, 7533bis, 754ibis, 



7732. 7744, and 7745, few. 

 Callithamnion Baileyi, 7523, few. 

 Callithamnionroseum, 752ibis, 7744, and 7754, few. 

 Ceramium fastigiatum, 7542 and 7348, few. 

 Ceramium rubrum 7542, 7551, 7551 (1907), and 7557, 



many; 7524, 7525, 754ibis, 7548, 7534, 7559, 75^0, 



756sbis, 7732, 7733, 7739, 7746, and 7749, few. 

 Ceramium strictum, 7746, few. 



