The Challenger Expedition was a scientific and exploring expedition carried out at the expense of the British Government by means of the ship Challenger, a frigate-built vessel of about 2000 tons, fully equipped with all the most improved scientific appliances for ascertaining the depth, temperature, currents, etc, of the ocean, and the character of the ocean bottom, and for amassing natural history specimens. The ship set sail on December the 7th, 1872, under the command of Captain (afterwards Sir) George Nares, Professor (afterwards Sir) Wyville Thomson being at the head of the scientific staff attached to the ship. In the course of the expedition the ship called at Madeira, Teneriffe, the Bermudas, Halifax, Nova Scotia, Cape Verde Islands, Cape of Good Hope, Kerguelen Islands, Melbourne, Sydney, Hong Kong, Japan, Valparaiso, etc, returning home by way of the Strait of Magellan, and arriving on May the 24th, 1876. During the three and a half years of the cruise the ship traversed about 70,000 nautical miles, and a vast amount of highly useful information was accumulated, the results being published at government expense in a great many volumes. Several popular works on the expedition were also published. Research Challenger Expedition
Actinopterygii is a division of bony fishes. The paired fins have broad bases and lack fleshy lobes. External nares are double, internal nares are absent. Scales are of the ganoid type. Research Actinopterygii
The nares (nostrils) serve as the opening for the nasal fossae, the two cavities in the middle of the face. The anterior nares open at the front of the face and the posterior
nares open into the nasopharynx. The posterior nares are somewhat smaller because they are narrowed by the mucousmembrane that helps filter the air. Research Nares
The nasalis muscle consists of two parts: the alar and the transverse. The alar is used when the nostrils are flared and runs along the side of the nose. The transverse runs diagonally and is used to wrinkle the nose. The nasalis is composed of three small muscles: the compressor nasi, the dilator naris posterior, and the depressor septi nasi. The compressor nasi is a small, thin muscle with a triangular shape. It runs along the bridge of the nose and depresses the cartilage and compresses the alae together. The depressor nasi is a short muscle that lies between the musclular structure and the mucousmembrane of the lip. It arises from the upper lip and extends to be inserted into the septum of the nose. It constricts the nares (nostrils) of the nose, the opposite action of the compressor nasi muscle. The dilatornares posterior is a small muscle that originates from the edge of the nasal notch and is inserted into the skin near the edge of the nostril. This muscle works with the dilator naris anterior, which is located in front of it,
to dilate the opening of the nares. All muscles of the nose are supplied by the facial nerve. Research Nasalis
The Atlantic Ocean is the sea to the west of Europe and east of America. The Atlantic Ocean is shaped somewhat like a letter 'S'. The coastlines of the Americas and Europe-Africa being approximately parallel. In the north, where extensive plains reach down to the sea, there are wide areas of continental shelf on both the eastern and western sides; that is, round the British Isles; around Newfoundland and North-Eastern USA. In contrast, the continental shelf in the South Atlantic Ocean is much narrower, especially where the plateaux of Africa and Brazil drop steeply to the coast. Running southwards in the middle of the Atlantic Ocean, half-way between the two continental masses and roughly parallel to their coasts, is a submarine ridge. This ridge, known as the Dolphin ridge in the North Atlantic Ocean and the Challenger ridge in the South Atlantic Ocean, occasionally rises above sea-level. Where this occurs are islands such as the Azores, St Paul's Rocks, Ascension Island, and Tristan da Cunha. Such islands as these are known as oceanic islands because they rise from the depths of the ocean; in contrast, islands like Newfoundland and the British Isles which rise only from the shallow floor of the continental shelf are known as continental islands. On each side of the Central Atlantic ridge are the great deeps, but the deepest Atlantic sounding yet taken is that of the Nares deep just north of Porto Rico.
The principal inlets and bays are Baffin'sand Hudson's Bays, the Gulf of Mexico, the Caribbean Sea, the North Sea or German Ocean, the Bay of Biscay, and the Gulf of Guinea.
The principal islands north of the equator are Iceland, the Faroe and British Islands, the Azores, Canaries, and Cape de Verd Islands, Newfoundland, CapeBreton, and the West India Islands; and south of the equator, Ascension, St Helena, and Tristan da Cunha.
The great currents of the Atlantic are the Equatorial Current (divisible into the Main, Northern, and Southern Equatorial Currents), the Gulf-stream, the North African and Guinea Current, the Southern Connecting Current, the Southern Atlantic Current, the CapeHorn Current, Kennel's Current, and the Arctic Current. The current system is primarily set in motion by the trade-winds which drive the water of the intertropical region from Africa towards the American coasts. The Main Equatorial Current, passing across the Atlantic, is turned by the S. American coast, along which it runs at a rate of 30 to 50 miles a day, until, having received part of the North Equatorial Current, it enters the Gulf of Mexico. Issuing thence between Florida and Cuba under the name of the Gulf-stream, it flows with a gradually expanding channel nearly parallel to the coast of the United States. It then turns north-eastward into the mid-Atlantic, the larger proportion of it passing southward to the east of the Azores to swell the North African and Guinea Current created by the northerly winds off the Portuguese coast. The Guinea Current, which takes a southerly course, is divided into two on arriving at the region of the north-east trades, part of it flowing east to the Bight of Biafra and joining the South African feeder of the Main Equatorial, but the larger portion being carried westward into the North Equatorialdrift. Kennel's Current, which is possibly a continuation of the Gulf-stream, enters the Bay of Biscay from the west, curves round its coast, and then turns northwest towards Cape Clear. The Arctic Current runs along the east coast of Greenland (being here called the Greenland Current), doubles Cape Farewell, and flows up towards Davis' Strait; it then turns to the south along the coasts of Labrador and the United States, from which it separates the Gulf-stream by a cold band of water. Immense masses of ice are borne south by this current from the Polar seas. In the interior
the North Atlantic there is a large area comparatively free from currents, called the Sargasso Sea, from the large quantity of sea-weed (of the genus Sargassum) which drifts into it. A similar area exists in the South Atlantic.
In the South Atlantic, the portion of the Equatorial Current which strikes the American coast below Cape St Roque flows southward at the rate of from 12 to 20 miles a day along the Brazil coast under the name of the Brazil Current. It then turns eastward and forms the South Connecting Current, which, on reaching the South African coast, turns northward into the Main and Southern Equatorial Currents. Besides the surface currents, an under current of cold water flows from the poles to the equator, and an upper current of warm water from the equator towards the poles. Research Atlantic Ocean
Abbreviations
Research Challenger Expedition
