WE have much pleasure in calling the attention of bryologists on this side of the Atlantic to this excellent handbook of the “Mosses of North America.” Many contributors have aided in its preparation, and a series of unfortunate disasters have delayed its publication at least ten years beyond what was expected, a delay which, however, has brought with it the compensation of greater completeness. Its foundation was laid by W. S. Sullivant, who contributed to the first edition of Gray's “Manual of the Plants of the Northern United States” in 1848 a synopsis of the mosses then known within the same territory, which were not more than about 200 species. In the second edition of the “Manual,” published in 1856, the number of species was doubled, and five plates were given to show the essential characters of he genera. Of both these two treatises a few separate copies were also struck off. At that time there were four excellent bryologists resident in the country who were vorking actively—Sullivant, Lesquereux, Austin, and fames—so that rapid progress was made. When the third edition of the “Manual” was issued, it was planned that Sullivant, in cooperation with Lesquereux, who worked at mosses with Schimper before he emigrated to America, where he has done such excellent work in fossil botany, should undertake an improved handbook of the nosses as a separate publication. Sullivant died in the pring of 1873 without this being carried into effect. His collection of specimens, drawings, and manuscript notes was bequeathed to the herbarium of Harvard University, which under the charge of Prof. Gray has for many years been the main centre for botanical work in the United states. It was planned that Mr. T. P. James, who belonged to Philadelphia, but who removed to live at Cambridge, and who was excellently qualified for the task, should take Sullivant's place in the undertaking, but he died in 1882, and Lesquereux, in old age with his sight failing, was again left alone. The book might have altogether collapsed if it had not been for the kind intervention of Dr. Sereno Watson, who now has charge of the Harvard Herbarium, and who, although not specially a bryologist, has taken upon himself the needful critical and editorial labour that was required to complete it. Manual of the Mosses of North America. By Leo Lesquereux Thos. James. 8vo, pp. 447, with Six Plates Illustrative of the Genera. (Boston: S. E. Cassino and Co.; London: Trubner and Co. 1884.)