On Friday evening, July 4, the Challenger arrived at Porta Delgada, the capital of the island of San Miguel, one of the easternmost of the Azores group. At Furnas, in San Miguel, there are two sets of boiling springs which were explored by the botanist of the expedition for algæ. Connected with one spring there is a basin full of intensely hot water always in ebullition. This had no algæ in it. Some diatoms were found in a hot sulphureous spring, probably derived from a cool spring which mingled with it. Certain Oscillatoria were also discovered in water so hot as to scald the hand. Unfortunately no exact record of temperature could be made, as no thermometers were at hand which registered sufficiently high.* A peculiar substance of the consistence of Indiarubber was found floating on one of the hot-springs. It burnt like the substance which it counterfeited, and in doing so emitted a similar smell. It resembled, too, as far as Mr. Moseley could remember, a peculiar elastic substance, a specimen of which is in the Kew herbarium among the lichens found upon the shores of an Australian lake. By some it has been held to be a mineral, and on this assumption some specimens are under Professor Maskelyne's care, in the British Museum.

The Challenger left the Azores for the Cape de Verde Islands on Wednesday, July 9. The Island of St. Vincent, one of the principal of the group, was visited. It has a flat central tract surrounded by high land, the former part being evidently the bottom of an ancient crater. The abundant plant is Lavandula rotundifolia. The tomato (introduced) has run wild everywhere. At the time of the visit there had been no rain for a year, but the island is said to become green after rain as if by magic. The rocks about tide-mark are covered with a band of incrustation composed of calcareous algæ. This incrustation is of several colours, white, pink, or cream-colour.

At St. Paul's Rocks, as at St. Vincent, there is a pinkish incrustation about tide-mark upon the rocks.† A green alga, which is constantly being loosened by the surf from the bottom, and floats upon the surface, is gathered by the "noddies" (Sterna stolida) for building their nests, but is not used by the "boobies" (Sula fusca). A few bushels of guano are to be found in rock-hollows, which is almost wholly soluble in nitric acid; but no diatoms-which abound in Peruvian guano—are

For some remarks by Mr. Archer on these algæ, &c., see "Journ. Linn. Soc. Botany," vol. xiv. p. 328.

+ Darwin, in his "Naturalist's Voyage," mentions that there is a similar incrustation on the coast of Ascension, resembling certain cryptogamic plants (Marchantia) often seen on damp walls. Of this he gives a beautiful woodcut.

to be found in the residue. St. Paul's Rocks are detached miniature islands about 1° N. of the equator, and having a longitude of 29° 15′ W., and are 500 miles from the nearest point of South America, lying about midway between that and the African coast. The rock approaches serpentine in structure. Not a trace of land vegetation, not even a lichen, is to be found here. "It is a remarkable fact," says Darwin, "that all the many small islands, lying far from any continent, in the Pacific, Indian, and Atlantic oceans, with the exception of the Seychelles and this little point of rock, are, I believe, composed either of coral or of erupted matter.”*

On Aug. 22, St. Vincent's Island was left by the Challenger for Bahia, to make her fourth section across the Atlantic. Bahia was reached on Sept. 15, after a successful but stormy voyage. Fernando de Noronha was stopped at, en route for Bahia, Sept. 1st and 2nd being spent here. The entire length of the whole chain of islands is about seven geographical miles, the group being situated in 3° 50′ S. lat., and being distant from Cape St. Roque, the nearest point in South America, more than 200 miles. On the main island there is a remarkable column of "phonolite," or clinkstone, more than 1,000 feet high, called "The Peak." The island is volcanic. The Cape gooseberry and the castor-oil plant grow wild here. The plant mentioned by Darwin as covered with fine pink flowers, but without a single leaf, is a euphorbiaceous plant-Jatropha gossypifolia, Linn. "Its bare stem," remarks Mr. Moseley," and branches render it a striking object amongst the green of the creepers when the forest is viewed from the sea." The flora is not very rich in species, and the same plants occur everywhere. There are neither ferns nor mosses, nor liverworts, though moist and shady places are not wanting, and lichens are very scarce. Mr. Darwin observes that the volcanic island of Fernando de Noronha, placed in many respects under nearly similar conditions, is the only other country where he has seen a vegetation at all like that of the Galapagos islands.†

After a stay of a little more than a week at Bahia the Challenger left for the Cape of Good Hope, touching at Tristan d'Acunha on the way thither. This group of islands has an area of about sixteen square miles, although stated by Grisebach (Vegetation der Erde) to be only two square miles in extent. A plant resembling a chrysanthemum-Chenopodium tomentosum -with strong-scented leaves, is used by the inhabitants, a decoction of it, under the name of "tea," being drunk with milk and sugar. It grows abundantly on Inaccessible Island, which is distant about 23 miles from Tristan. Inaccessible Island is † Ibid.

* Darwin's "Naturalist's Voyage."

covered with "tussock" grass (Spartina arundinacea?) which forms an enormous penguin "rookery," being so thick as almost to be impenetrable. This grass has a habit, like that of the Falkland Islands (Dactylis caspitosa), of growing to five or six feet, springing in tufts, and forming massive boles or clumps at its base, composed of contorted root-fibres matted together. These are so tough as to require an axe to cut them. The grass thrives best where it is saturated with penguin dung. The close similarity of the three islands of the Tristan group points to a former close connexion. The presence of many plants here may be accounted for by the existence of a Cape Horn current which comes sweeping up to the islands. Part, too, of the Brazilian current, which turns from the coast of South America, brings many seeds, which, however, being tropical, do not germinate. These are known to the settlers as "sea-beans," from the belief that they grow at the bottom of the neighbouring sea. One of these is the bean of a leguminous tree common at Bahia, while another is identical with a seed cast up upon the Bermudas, which, under the same name, is worn as a "curiosity " on watchchains. The thrush and bunting, the only strictly land birds which inhabit the islands,* feeding, as they do, upon berries, have also assisted in spreading plants from one island of the group to another.

By the time that the month of November had come round the Challenger had arrived at Simon's Bay, Cape of Good Hope. After a stay of about six weeks here the journey was resumed southward, † Prince Edward's Island being the first haltingplace, though no landing could unfortunately be effected here. After leaving the Cape dredgings were taken a little to the southward at depths of from 100 to 150 fathoms. The animal life was found to be abundant, the fauna being generally like that of the North Atlantic, many species even being identical with those on the coasts of Britain and Norway. From two dredgings between Prince Edward's Island and the Crozets at depths of 1,375 and 1,600 fathoms, it was further demonstrated that here, in the south of the Indian Ocean, we have principally to do with the same deep sea fauna as the Atlantic Ocean presents. From the station between the above two groups an Ostracod was obtained in comparison with which all previous ones are pigmies, its shell having a length of 25 millimetres and a height of 16 millimetres. It is said that one of a

A coot, according to Darwin ("Naturalist's Voyage"), is also to be found here; from which he deduces that "the waders, after the innumerable web-footed species, are generally the first colonists of small isolated islands."

+ I have not succeeded, despite of some pains to ascertain them, in finding out the exact dates of the arrival at and departure from the Cape.

smaller size, Cytherina Baltica, exists in the transitional mountain ranges of Gothland.* From this and other similar cases it is suggested that at great depths gigantic forms of genera and families have been preserved which never attain such a size at the surface and in shallow waters.t

At Marion Island a halt was made, and Mr. Moseley had a day at his disposal for collecting plants. The flora was found to be very similar to that of Kerguelen's Island, but was poorer in species. No landing was made at the Crozets. On Jan. 7, 1874, the Challenger arrived at Kerguelen's Island, and remained in the neighbourhood till Feb. 1. Here only two plants were found new to the flora, viz. a Cerastium and an Uncinia. Large collections were made of the famed Kerguelen's Land cabbage (Pringlea antiscorbutica, Hooker), and of Lyallia Kerguelensis. From observations on Kerguelen's Island and elsewhere it is concluded that the higher forms of crustacea are almost entirely absent on the shores of the Antarctic islands, while in deep water here (as has been already witnessed at 300 fathoms) they are present in almost the same abundance as in the tropics. It is also concluded that the characteristic crustacea of the surface-water fauna of the Antarctic islands belong to the Isopoda and Amphipoda; that is, to forms which carry the ova in pouches up to their full period of development. As the Echinodermata, too, show, as has been observed by Professor Wyville Thomson, an unusual number of species in which the young develope direct in the maternal pouch, conditions must exist which

Second letter from Dr. Suhm to Professor Siebold, dated Sydney, April 1874. "Siebold and Kölliker's Zeitschr." Bd. xxiv.

For instance, the President of the Linnæan Society received from Professor Wyville Thomson a drawing of a specimen of a Gymnoblastic Hydroid "of such colossal dimensions that the largest form hitherto known sinks in comparison with it into utter insignificance." It was brought up by the trawl on June 17, 1875, in the North Pacific, from a depth of 2,875 fathoms. The "Hydranth was 9 inches across from tip to tip of the expanded (non-retractile) tentacles, and the "Hydrocaulus" was 7 ft. 9 in. high! "That the enormous depths," remarks Mr. Allman, "from which this colossal Hydroid has been brought up should favour the development of gigantic representatives of the diminutive forms of shallower zones, and that in the tenants of these sunless regions of the sea we should find colours not less vivid than those of their light-loving relatives, are facts full of significance." See "Nature," vol. xii. p. 555.

"Journ. Linn. Soc. Botany," vol. xlv. p. 387.

§ The fauna and flora of this island have also been described lately by the naturalist attached to the Venus Transit Expedition. See "First Report of the Naturalist attached to the Transit of Venus Expedition to Kerguelen's Island, Dec. 1874," by the Rev. A. E. Eaton. "Proc. Royal Soc." vol. xxiii. p. 351.

are unfavourable to a free-swimming stage of development.* Corinthian Bay, in Yong Island, of the Heard group, was reached on the evening of Feb. 6, but, unfortunately, a change of weather prevented a stay here of more than two hours. "Numerous glaciers come right down to the shore. The vegetation is most scanty, most of the land surface not covered with ice being bare." Only five flowering plants, apparently of the same species as at Kerguelen-among them a much-dwarfed Pringlea and one or two mosses, and a liverwort-were found.†

From deep soundings (1,375 to 1,900 fathoms) taken before reaching the Crozets the bottom was found to be composed entirely of Orbulina and Globigerina dead, and of the same species as those on the surface. Some Coccoliths and Rhabdoliths were also found. Samples of these sea-bottoms were of the purest carbonate of lime yet obtained; and when placed in a bottle and shaken up with water they looked like a quantity of sago. South of Heard Islands the bottom, as shown by soundings at 1,260 fathoms, was quite different, "being one mass of diatoms."

The most southerly station was reached on Feb. 14, being in lat. 65° 42′ S., and long. 79° 49′ E.-just outside of the Antarctic circle, the "threshold" of which is at 66° 32′ S. On Feb. 24, in trying to get under the lee of an iceberg, the Challenger was brought by a strong current into collision with it, and had her jib-boom carried away. At this time the ship was really in some danger from the numerous icebergs. On the following day the Challenger was within 15 miles of the position of the socalled "Termination Land " laid down on a chart sent by Lieut. Wilks to Capt. Ross. As no signs of it were to be seen it was concluded that its existence was mythical. Laboratory work in the southern latitude was very unpleasant, the microscopes and other instruments being so cold that it was anything but agreeable to handle them, in rooms in which the temperature averaged 25° F. for several days. Dredging, too, was a critical operation, as the gear, becoming stiffened, was liable to part. Berg and floe ice were examined, and were found to contain the usual diatoms. In 48° 18' S. lat. the fauna was already fully that of warmer zones. The Indo-Australian current therefore extends farther southwards than had hitherto been expected. Indeed, certain surface-animals of the warm Indian current from the N.W. were observed as soon as 50° 15′ lat. S. was reached.§ • Von Willemoes-Suhm.-" Proc. Royal Soc." vol. xxiii. p. 351. + Moseley. Ibid.

"The Antarctic. A letter from H.M.S. Challenger." By Prof. Wyville Thomson, in "Good Words," July 1875. See also a communication "On Dredgings and Deep-sea Soundings in the South Atlantic, in a Letter to Admiral Richards, C.B., F.R.S."-" Proc. Royal Soc." vol. xxii. p. 427. § Von Willemoes-Suhm.

Ibid.