BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 



477 



necessitating a new set of numbers, which were substituted for the old. In all, 50 species 

 were recorded on the rocks during the 15 months' study, the list being as follows: 



List of algce found on Spindle Rocks. 



CYANOPHYCE^E. 



1. Calothrix scopulorum. 



3. Ulothrix implexa. 



4. Ulva Lactuca. 



5. Ulva Lactuca var. rigida. 



6. Enteromorpha crinita. 



7. Enteromorpha intestinalis. 



13. Ectocarpus aecidioides. 



14. Ectocarpus confervoides. 



15. Ectocarpus fasciculatus. 



16. Ectocarpus granulosus. 



17. Ectocarpus ovatus. 



18. Ectocarpus penicillatus. 



19. Ectocarpus siliculosus. 



20. Ectocarpus tomentosus. 



2 1 . Sorocarpus uvaeformis. 



22. Desmotrichum balticum. 



23. Desmotrichum undulatum. 



24. Phyllitis fascia. 



37. Porphyra laciniata. 



38. Acrochaetium secundatum. 



39. Acrochaetium virgatulum. 



40. Nemalion multifidum. 



41. Callithamnion Baileyi. 



42. Callithamnion corymbosum. 



43. Ceramium rubrum. 



Pvivularia atra. 



CHLOROPHYCEiE. 



8. Enteromorpha prolifera. 



9. Cladophora gracilis. 



10. Cladophora lanosa. 



11. Chadophora lanosa var. uncialis. 



12. Codiolum gregarium. 



PILEOPHYCEiE. 



25. Punctaria plantaginea. 



26. Scytosiphon lomentarius. 



27. Desmarestia viridis. 



28. Chordaria flagelliformis. 



29. Mesogloia divaricata. 



30. Myrionema corunnae. 



31. Chorda filum. 



32. Chorda tomentosa. 

 ^- Laminaria Agardhii. 



34. Laminaria Agardhii var. vittata. 



33. Fucus vesiculosus. 



36. Sargassum Filipendula. 



RHODOPHYCEiE. 



44. Chondria dasyphylla. 



45. Dasya elegans. 



46. Polysiphonia fibrillosa. 



47. Polysiphonia urceolata. 



48. Polysiphonia violacea. 



49. Chondrus crispus. 



50. Champia parvula. 



The detailed records of the accompanying eight charts (no. 267-274) have been 

 given in the legends, and it is only necessary in this account to present the most 

 important conclusions from the study of the rocks throughout the seasons. 



During the winter the tops of the rocks were scraped perfectly bare of vegetation, 

 and even of barnacles, by the floating ice carried back and forth through the channel 

 by the swft tides. a The conditions at the end of the winter of 1905 are shown in chart 

 267, recorded March 17, 1905. It is interesting to compare this chart with chart 274, 

 of December 30, 1904, which shows algae well distributed over the upper portion of 

 almost every rock. That vegetation had been entirely swept away in the two and one- 

 half months elapsing between the two records, and no algae had as yet formed a per- 

 ceptible new growth. This history is probably that of every bowlder along the shore 



n There are, however, winters at Woods Hole when practically no floating ice is present, and at such times the alga are 

 not affected. 



