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 alge jound on Spindle Rocks. 
CYANOPHYCE. 
1. Calothrix scopulorum. | 2. Rivularia atra. 
CHLOROPHYCE#. 
3. Ulothrix implexa. 8. Enteromorpha prolifera. 
4. Ulva Lactuca. g. Cladophora gracilis. 
5. Ulva Lactuca var. rigida. to. Cladophora lanosa. 
6. Enteromorpha crinita. 11. Chadophora lanosa var. uncialis. 
7. Enteromorpha intestinalis. 12. Codiolum gregarium. 
PHHOPHYCES. 
13. Ectocarpus ecidioides. 25. Punctaria plantaginea. 
14. Ectocarpus confervoides. 26. Scytosiphon lomentarius. 
15. Ectocarpus fasciculatus. 27. Desmarestia viridis. 
16. Ectocarpus granulosus. 28. Chordaria flagelliformis. 
17. Ectocarpus ovatus. 29. Mesogloia divaricata. 
18. Ectocarpus penicillatus. 30. Myrionema corunne. 
19. Ectocarpus siliculosus. 31. Chorda filum. 
20. Ectocarpus tomentosus. 32. Chorda tomentosa. 
21. Sorocarpus uveformis. 33. Laminaria Agardhii. 
22. Desmotrichum balticum. 34. Laminaria Agardhii var. vittata. 
23. Desmotrichum undulatum. 35. Fucus vesiculosus. 
24. Phyllitis fascia. 36. Sargassum Filipendula. 
RHODOPHYCE. 
37. Porphyra laciniata. 44. Chondria dasyphylla. 
38. Acrochetium secundatum. 45. Dasya elegans. 
39. Acrochetium virgatulum. 46. Polysiphonia fibrillosa. 
40. Nemalion multifidum. 47. Polysiphonia urceolata. 
41. Callithamnion Baileyi. 48. Polysiphonia violacea. 
42. Callithamnion corymbosum. 49. Chondrus crispus. 
43. Ceramium rubrum. 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.* 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 algz 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 alge had as yet formed a per- 
ceptible new growth. This history is probably that of every bowlder along the shore 
@ There are, however, winters at Woods Hole when practically no floating ice is present, and at such times the alge are 
not affected. 
