Unpublished paper, 'On the sea saw-dust [Trichodesmium] of the Pacific' by John Denis Macdonald Macdonald provides a description of sea sawdust, a genus of filamentous cyanobacteria observed in the South Pacific Ocean. Annotations in pencil throughout. Includes one page of figures of the sea sawdust. Subject: Algology Received 13 January 1857. Read 26 February 1857. Communicated by Captain [Henry Mangles] Denham. Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 8 of the Proceedings of the Royal Society as 'On the sea saw-dust of the Pacific'. 1856