49° BULLETIN OP THE BUREAU OF FISHERIES. 



The main channel near Hadley Rock (station 121) has a bottom of sand and stones. 

 There was an abundance of Laminaria Agardhii, Agardhiella tenera, Chondrus crispus, and 

 Gracilaria multipartita, together with a few plants of Sargassum Filipendula. Dredgings 

 of previous years have shown that Callithamnion roseum grows on shells in the narrower 

 portion of the passage (Woods Hole proper), and also Scinaia furcellata. The passage on 

 the south is bordered by ledges, chiefly submerged, and these are covered with heavy 

 growths of algae. The reader may obtain a general idea of the character of the algal 

 life on these rocks bordering the channel from chapter iv, page 476, "A Report on the 

 Algae of Spindle Rocks, Woods Hole Harbor," a small group of rocks (destroyed in the 

 summer of 1905) that formerly lay between^ Grassy Ledge and Red Ledge. These sub- 

 merged ledges are difficult to study, but detailed examinations of some of them carried 

 on through various seasons of the year would undoubtedly give some interesting results. 



The algal life on the bottom of the harbor of Woods Hole and in the two ships' chan- 

 nels that lead into it from Vineyard Sound on either side of Great Ledge is very sparse. 

 The bottom is hard sand and sandy mud, unfavorable for extensive growths of algse. 

 A haul (station 4) inside of Great Ledge in 2 to 5 fathoms over a sandy bottom gave a few 

 plants of Antithamnion cruciatum, Ceramium rubrum, Chondrus crispus, Gracilaria multi- 

 partita, Grinnellia americana, Mclobesia Lejolisii (on Zostera), and Phyllophora Brodiaei. 



(4) ROBINSONS HOLE. 



Robinsons Hole, along the west end of Naushon (stations 20, 21 and 22), has a 

 rich algal flora over a stony bottom in 2 to 3^ fathoms. There was an abundance of: 



Cystoclonium purpurascens var. cirrhosum, 



and 22. 

 Hildenbrandia prototypus, 21 and 22. 

 Lithothamnion polymorphum , 21. 

 Phyllophora Brodisei, 20, 21 and 22. 

 Phyllophora membranifolia, 22. 

 Rhodymenia palmata, 21 and 22. 

 Scinaia furcellata, 21. 

 Spermothamnion Turneri, 20 



Chorda filum, 21 and 22. 

 Desmarestia aculeata, 20, 21 and 22. 

 Desmarestia viridis, 20 and 22. 

 Laminaria Agardii var. vittata, 21, 

 Antithamnion cruciatum, 22. 

 Ceramium fastigiatum, 20. 

 Ceramium rubrum, 20, 21 and 22. 

 Chondrus crispus, 20, 21 and 22. 

 Cystoclonium purpurascens, 20 and 22. 



In small quantities were found : 



Cladophora gracilis, 20 and 21. 

 Cladostephus verticillatus, 21. 

 Ectocarpus siliculosus, 21. 

 Laminaria Agardhii, 22. 

 Leathesia difformis, 20. 

 Phyllitis fascia, 22. 

 Ahnfeldtia plicata, 21 and 22. 



Station 23, off the island of Pasque, at the entrance to Robinsons Hole, showed the 

 presence of much Antithamnion cruciatum, Chondrus crispus, Phyllophora membrani- 

 folia, Rhodymenia palmata, and a few plants of Desmarestia aculeata, Desmarestia viridis, 

 and Polysiphonia elongata. 



This flora has a mixed composition including forms characteristic of both the cool- 

 and warm-water sublittoral formations, indicating that the summer conditions of Robin- 

 sons Hole are somewhat midway between those of the open and those of tne sheltered 

 waters of the Sound and Bay. 



Ceramium strictum, 20. 

 Champia parvula, 20, 21 and 22. 

 Corallina officinalis, 20 and 21. 

 Dasya elegans, 21. 

 Lomentaria uncinata, 21 and 22. 

 Polysiphonia fibrillosa, 20. 

 Polysiphonia nigrescens, 20 and 22. 



