BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 



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Chart 271. — Distribution of algae on Spindle Rocks, July 22, 1905 



The only conspicuous green alga was Ulva Lacluca var. rigida (5), now full grown and forming large 

 patches on some of the rocks. There was a very well-defined brown zone just below low-water mark 

 (the dotted line) composed of Chordaria flagelliformis (28) and old Scytosiphon lomentarius (26). Ecto- 

 carpus conferuoides ( 14) was plentiful on the Chordaria and Scytosiphon. Phyllitis fascia had disappeared. 

 Nemalion multifidum (40) fringed most of the rocks at low-water mark, and below was a characteristic red 

 zone of Polysiphonia violacea (48) and Ceramium rubrum (43) mixed with the Chordaria, and with Chon- 

 drus crispus (49) abundant from 1-5 feet below low water. 



Listofalgas: Calothrix scopulorum, i, small patches on barnacles and rocks; Rivularia atra, 2, on 

 barnacles; Ulothrix implexa, 3, on Pyramid Rock; Ulva Lactuca var. rigida, 5, abundant on tops of 

 rocks; Enter omorpha intestinalis , 7, few patches; Cladophora gracilis, 9, few tufts; Codiolum gregarium, 

 12, on barnacles; Ectocarpus confervoides, 14, abundant on Chordaria and Scytosiphon; Scytosiphon 

 lomentarius, 26, much old growth; Chordaria flagelliformis , 28, abundant; Mesogloia divaricata, 29, few 

 patches; Chorda filum, 31, large patches; Laminaria Agardhii, 33, few groups; Fucus vesiculosus, 35, 

 few plants; Nemalion multifidum, 40, abundant; Ceramium rubrum, 43, abundant; Chondriadasyphylla, 

 44, few plants; Polysiphonia violacea, 48, abundant; Chondrus crispus, 49, abundant. 



