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daughter of Alexander II., emperor of Russia, was celebrated at St. Petersburg, and the bride and bridegroom made their public entry into London on 12th March. The duke still devoted himself to his profession, showing complete mastery of his duties and unusual skill in naval tactics. He was promoted rear-admiral, 30th December 1878; vice-admiral, 10th November 1882; admiral, 18th October 1887; and received his baton as admiral of the Fleet, 3rd June 1893. He commanded the Channel Fleet, 1883-84; the Mediterranean Fleet, 1886-89 ; and was commander-in-chief at Devonport, 1890-93. He always paid the greatest attention to his official duties, and was most efficient as an admiral. On the death of his uncle, Ernest II., duke of SaxeCoburg and Gotha, 22nd August 1893, the vacant duchy fell to the duke of Edinburgh, for the Prince of Wales had renounced his right to the succession. At first regarded with some coldness as a “ foreigner,” he gradually gained

popularity, and by the time of his death, 30th July 1900, he had completely won the good opinion of his subjects. The duke was exceedingly fond of music, and an excellent violinist, and took a prominent part in establishing the Royal College of Music. He was also a keen collector of glass and ceramic ware, and his collection, valued at half a million of marks, was presented by his widow to the “ Yeste Coburg,” near Coburg. When he became duke of Saxe-Coburg he surrendered his English allowance of £15,000 a year, but the £10,000 granted in addition by Parliament on his marriage he retained in order to keep up Clarence House. The duke had one son, who died unmarried, 6th February 1899, and four daughters. The third daughter, Princess Alexandra Louisa Olga Victoria, married the hereditary Prince Ernest of Hohenlohe-Langenburg, who became regent of the duchy of Coburg during the minority of the deceased duke’s nephew, the young duke of Albany, to whom the succession fell. (g. f. b.1

ALGr£. THE Latin word Alga seems to have been the equivalent of the English word “seaweed,” and probably stood for any or all of the species of plants which form the “ wrack ” of a seashore. When the word “Algae” came to be employed in classification as the name of a class, an arbitrary limitation had to be set to its signification, and this was not always in keeping with its original meaning. The absence of differentiation into root, stem, and leaf, which prevails among seaweeds, seems, for example, to have led Linnaeus to employ the term in the Genera Plantarum for a subclass of Cryptogamia, the members of which presented this character in a greater or less degree. Of the fifteen genera included by Linnaeus among Algae, not more than six, viz. :—Chara, Fucus, Ulva, and Conferva, and in part Tremella and Byssus, would to-day, in any sense in which the term is employed, be regarded as Algae. The excluded genera are distributed among the Liverworts, cation*' Lichens, and Fungi; but notwithstanding the great advance in knowledge since the time of Linnaeus, the difficulty of deciding what limits to assign to the group to be designated Algce still remains. It arises from the fact that Algae, as generally understood, do not constitute a homogeneous group, suggesting a descent from a common stock. Among them there exist, as will be seen hereafter, many well - marked but isolated natural groups, and their inclusion in the larger group is generally felt to be a matter of convenience rather than the expression of a belief in their close inter-relationship. Efforts are therefore continually being made by successive writers to exclude certain outlying sub-groups, and to reserve the term Algce for a central group reconstituted on a more natural basis within narrower limits. It is perhaps desirable, in an article like this, to treat of Algae in the widest possible sense in which the term may be used, an indication being at the same time given of the narrower senses in which it has been proposed to employ it. Interpreted in this way, the place of Algae in the vegetable kingdom may be shown by means of a table :— r Myxomycetes Thallophyta j Fungi Algce The Vegetable Cryptogamia Bryophyta Kingdom Pteridophyta v ^ lAngiosperms Algae in this wide sense may be briefly described as the aggregate of those simpler forms of plant life usually

devoid, like the rest of the Thallophyta, of differentiation into root, stem, and leaf; but, unlike other Thallophyta, possessed of a colouring matter, by means of which they are enabled, in the presence of sunlight, to make use of the carbonic acid gas of the atmosphere as a source of carbon. It is true that certain Bryophyta (Marchantiaeece, Anthocerotece) possess a thalloid structure similar to that of Thallophyta, and are at the same time possessed of the colouring matter of the Green Algse. Their life-cycle, however, the structure of the reproductive organs, and their whole organization proclaim them to be Bryophyta. (See Muscine^:, ninth ed., and Bryophyta.) On the other hand certain undoubted animals {Stentor, Hydra, Bonellia) are provided with a green colouring matter by means of which they make use of atmospheric carbonic acid. A more important consideration is the occasional absence of this colour in species, or groups of species, with, in other respects, Algal affinities. Such aberrant forms are to be regarded in the same light as Cuscuta and Orobanchacece, for example, among Phanerogams. As these non-green plants do not cease to be classed with other Phanerogams, so must the forms in question be retained among Algae. In all cases the loss of the colouring matter is associated with an incapacity to take up carbon from so simple a compound as carbonic acid. Further discussion of the general characters of Algae will be deferred in order to take a brief survey of the subdivisions of the group. For this purpose, there will be adopted the classification of Algae into four sub-groups, founded on the nature of the colouring matters present in the plant:— 1. CYAHOPHYGEiE, or Blue-green Algae. 2. ChlorophycevE, or Green Algae. 3. Pha:ophyce.e, or Brown Algae. 4. Rhodophyce,®, or Red Algae. The merits and demerits of this system will appear during the description of the characters of the members of the several subdivisions. 1. Cyanophycea:.1—This group derives its name from the circumstance that the cells contain in addition to the green colouring matter, chlorophyll, a blue-green colouring matter to which the term phycocyanin has been applied. To the eye, however, members of this group present a greater variety of colour 1

Includes (exclusive of Bacteriaceae) :— 1. CoccogoTiece—2 families, 29 genera, 253 species. 2. Hormogonece—6 families, 59 genera, 701 species. (Engler and Prantl’s Pjlanzenfamilien).