note * page 857 Owing to ill-health, Mr Stuart Ridley has not hitherto been able to proceed with the description of the new species. I am, however, greatly indebted to him for a preparatory list of the collection. A probably new genus is represented by one of the specimens. I sent to the Australian Museum at Sydney a collection of large specimens, which probably contains additional new species.

note † page 857 Vide my paper on the Calcareous Formations of this Group, Trans. Editi. Roy. Soc., vol. xxxii. part 3Google Scholar.

note * page 858 One that I found had enclosed or grown around a piece of pumice.

note † page 858 Vide p. 883, where this gradual slope is described as a constant feature of the outer side of a reef in these seas.

note ‡ page 858 An undescribed species.

note § page 858 Vide p. 883.

note * page 859 Mr S. Ridley informs me that there are two apparently distinct species in my collection, one being probably new.

note † page 859 The Stylasteridse, which Professor Mosely has placed with the other hydrozoan corals in the sub-order Hydrocorallinse, did not frequently come under my notice among the reefs of these islands, and then only as small specimens.

note * page 860 Sometimes written Rhodareea.

note † page 860 From a depth of 13½ fathoms I brought up a living fragment of this Anthelia.

note * page 861 Probably a new species, as Mr Kidley informs me.

note † page 861 Coral Beefs, 1842, p. 81.Google Scholar

note ‡ page 861 This coral, according to Mr Quelch, closely resembles M. cerealis of the West Indies. Its range of depth appears to be 2 to 13 fathoms.

note § page 861 For some further particulars of my coral-soundings, vide a short paper in the Annals and Magazine of Natural History, June 1884.

note * page 862 Vide footnote on p. 859.

note * page 863 Voyage of H.M.S. Fly, 1847, vol. i. p. 119Google Scholar

note * page 866 This was the only occasion on which I obtained this Orbicella. Numerous other organisms were found in or upon this mass of rock, such as Ophiuroids, a Comatula, Olivœ, Arcœ, a small eel-like fish, &c.

note † page 866 This alga grows on reef-flats and in the wash of the surf.

note ‡ page 866 More than one species of Heteropsammia live in these depths of from 20 to 40 fathoms, H. multilobata being common. The majority, if not all, were characterised by the presence of the Sipunculus (Aspidosiphon).

note * page 867 Voyage autour du Monde, 2nd edit, Paris, 1772, tome ii. p. 183Google Scholar.

note † page 867 Dana's Corals mid Coral Islands, and Couthouy's Remarks on Coral Formation, &c.

note * page 868 For the description of the elevated reefs and their foundations, I must refer the reader to my paper in the Trans. Edin, Roy. Soc., vol. xxxii. part 3Google Scholar.

note * page 871 A east of 400 fathoms to the west and another of 260 to the north-east failed to reach the bottom.

note † page 871 Hand specimens from one of these hills were in part chalky. Vide my paper on the “Calcareous Formations,” Trans. Edin. Boy. Soc., vol. xxxii. part 3, pp. 563, 575Google Scholar.

note * page 872 Atolls only a mile or less in width.

note * page 874 Vide a paper on the Composition of some Coral Limestones, &c., from the South Sea Islands, read before the Eoyal Society of N.S.W., October 6, 1880.

note † page 874 These “holes” in the shore-reefs are not uncommonly found in other islands of this group. They are often termed “boat-harbours,” when accessible ; and are usually 100 to 150 yards across, with depths of 20 fathoms and under.

note * page 875 Dolerites and other dense basic rooks, all much altered and sometimes schistose.

note * page 876 I am greatly indebted to the Hydrographer, Captain W. J. L. Wharton, R. N., for an early copy of the chart of Bougainville Strait.

note * page 877 In my paper on the recent Calcareous Formations, I have shown that Alu, the main island, has been formed by the upheaval of a succession of barrierreefs that have grown outwards on a bottom of foraminiferous volcanic muds from a nucleus of volcanic rock.

note † page 877 I visited several portions of this line of reef. A detailed description is, however, unnecessary.

note ‡ page 877 The island of Fauro is of volcanic formation. The rocks composing it are mostly andesites, together with altered dolerites, diorites, quartz-felsites, dacites, &c. Similar rocks are found in the other islands and islets of the straits. No traces of activity came under my notice in any of the volcanic islands that I visited.

note * page 879 The bearing of this fact is referred to on page 867.

note * page 880 In a short paper, published in the Annals and Magazine of Natural History for June 1884, I have dealt more particularly with the soundings.

note * page 883 I learned from a pearl diver in these islands that he had frequentlynoticed, when diving on the outer sides of the reefs, that at the base of a precipitous slope in depths of 15 to 20 fathoms, the rock overhung to such an extent that he was able to get underneath the projecting portion. This was evidently due to the outward growth of the corals on the face of the declivity.

note * page 884 I first described this view of the formation of barrier-reefs in a short paper, entitled “Suggestions as to the Formation of Barrier Reefs,” &c., which was read before the Linnean Society, New South Wales, in October 1884 (Proc., vol. ix. part 4). At that time I was in ignorance of the fact that substantially the same explanation had been proposed many years before by Professor Joseph Le Conte in the instance of the Florida barrier-reefs. In 1856 Professor Le Conte pointed out that the explanation of the circumstance that the Florida peninsula had been formed by a succession of barrier-reefs, instead of by a continuous fringing-reef, was to be found in the fact that, since corals will not grow on muddy shores or in water upon the bottom of which sediment is collected, the favourable conditions can only be obtained some distance from the shore. There, as he remarked, a barrier-reef would be formed, limited on one side by the muddiness, and on the other by the depth of the water (vide American Journal of Science, 2nd series, vol. xxiii. p. 46, and Nature, October 14, 1880). This view seems to have attracted scarcely any attention since it was first proposed ; but the circumstance that I arrived independently at the same conclusion with reference to the barrier-reefs of the Solomon Group is one that lends it very powerful support.

note * page 885 Such a reef covered by 5 fathoms of water lies south of Choiseul Bay.

note * page 887 These depths and other particulars are to be found in my paper in the Ann. & Mag. Nat. Hist., June 1884Google Scholar. More recent data have led me to change some of the views there expressed.

note * page 888 Dana, 's Corals and Coral Islands (1872), p. 115Google Scholar; Darwin, 's Coral Reef (1842), p. 83.Google Scholar

note † page 888 Memoirs, , American Academy of Arts and Sciences, vol. xi. part ii. No. 1, 1885.Google Scholar

note * page 889 Coral Reefs (1842), p. 84.Google Scholar

note † page 889 Vide Trans. Edin. Roy. Soc., vol. xxxii. part iii. p. 545Google Scholar.

note * page 890 This mode of growth is one of the chief points on which Mr Murray dwells. My observations go to support his view.

note * page 892 Proc. Roy. Soc. Edin., 1879–1880, x. 505.Google Scholar

note * page 894 Coral Reefs (1842), p. 14.Google Scholar

note † page 894 Corals and Coral Islands (1872), p. 229Google Scholar; vide also his earlier works.

note ‡ page 894 Mem. Amer. Acad. Arts and Sci., vol. xi. part ii. No. i. 1885, p. 127.Google Scholar

note § page 894 Animal Life, vol. xxxi. Internal;. Scient. Ser., p. 413.

note * page 895 Nature, Nov. 2, 1882, and Feb. 21, 1884.Google Scholar

note † page 895 Nature, March 8 and 29, 1883.Google Scholar

note * page 896 These grooves are often preserved on flats of coral rock that have been recently elevated a few feet or more above the sea.

note * page 897 The Foraminifer, Tinoporus baculatus, is also commonly found in the sand of the Solomon Island beaches.

note † page 897 Similar deposits of Orbitolites are forming off the Australian shore between the inner reefs of the great barrier-reef. Mr Beete Jukes found that the dredge, from depths of 15 or 20 fathoms, was sometimes filled with Orbitolites: these organisms seemed in some places to make up the whole sand of a beach of a coral island (Student's Manual of Geology, 1862, p. 131). The important part taken by Halimedœ and Nulliporœ in the composition of deposits of coral reefs attracted the attention of Mr Darwin. We are informed by him that joints of a Halimeda and small fragments of Nulliporœ, all dead, thickly strew the bottom in depths greater than 90 fathoms, off Keeling Atoll; and also that Capt. Allen, E. N,, in his survey of the "West Indies, found that in depths between 10 and 200 fathoms the armings very generally came up covered with the dead joints of a Halimeda (Coral Reefs, 1842, p. 86).

note * page 898 Trans. Edin. Roy. Soc., vol. xxxii. part 3Google Scholar.

note † page 898 From a depth of 100 fathoms there came up on one occasion dead coral fragments in addition to the sand.

note * page 900 Proc. Roy. Soc. Edin., vol. x. p. 505Google Scholar.

note * page 902 MrForbes, H. O., in his recent account of Keeling Atoll, refers to the welling up of dark sulphureous water in the lagoon, by which the corals, molluscs, fish, and other organisms were killed over a large area of the basin (A Naturalist's Wanderings in the Eastern Archipelago, 1885, p. 22Google Scholar). Such an agency can scarcely be exceptional, and probably takes a part in the formation of lagoons.

note * page 903 I found living reef-corals on one occasion at a depth of 40 fathoms.