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 1715, in which year was published his Address to Persons of Quality and Estate, containing suggestions for the establishment of special hospitals, schools and theological colleges, many of his proposals being afterwards carried into effect. Nelson married a Roman Catholic, Lady Theophila Lucy, daughter of the earl of Berkeley, and widow of Sir Kingsmill Lucy of Broxbourne.

 NELSON, a river of Keewatin district, Canada, discharging the waters of Lake Winnipeg in a north-easterly direction into Hudson Bay. It drains an area of 360,000 sq. m. and, including its tributary the Saskatchewan, is 1450 m. long. It is navigable for small steamers for a distance of about 80 m., after which it is unnavigable except for canoes. It has a total fall between the lake and sea of 710 ft. Here its chief tributary is the Burntwood. Norway House at its source and York Factory at its mouth are important stations of the Hudson’s Bay Company.  NELSON, a town of British Columbia, situated on the west arm of Kootenay lake. Pop. (1906) about 5000. It is the commercial, administrative and railroad centre of the east and west Kootenay districts. It is the northern terminus of a branch of the Great Northern railway and is also connected by rail and steamboat with the main line of the Canadian Pacific railway at Revelstoke and with the Crow’s Nest line of the same system at Kootenay landing. It has direct railway communication with Rossland, Grand Forks and Greenwood.  NELSON, a municipal borough in the Clitheroe parliamentary division of Lancashire, England, 32 m. N. from Manchester by the Lancashire & Yorkshire railway. Pop. (1891) 22,754, (1901) 32,816. It is of modern growth, possessing a town hall, market hall, free library, technical school, pleasant park and recreation grounds, and an extensive system of electric tramways and light railways, connecting with Burnley and Colne. Its chief manufacture is cotton. It was incorporated in 1890, and the corporation consists of a mayor, 6 aldermen and 18 councillors. Area, 3466 acres.  NELSON, a seaport of New Zealand, the seat of a bishop and capital of a provincial district of the same name; at the head of Blind Bay on the northern coast of the South Island. Pop. (1906) 8164. The woods and fields in the neighbourhood abound with English song-birds, and the streams are stocked with trout; while the orchards in the town and suburbs are famous for English kinds of fruit, and hops are extensively cultivated. The town possesses a small museum and art gallery, literary institute, government buildings, and boys’ and girls’ schools of high repute. The cathedral (Christ Church) is finely placed on a mound which was originally intended as a place of refuge from hostile natives. It is built of wood, the various native timbers being happily combined. Railways connect the harbour with the town, and the town with Motupiko, &c. The harbour, with extensive wharves, is protected by the long and remarkable Boulder Bank, whose southern portion forms the natural breakwater to that anchorage. The settlement was planted by the New Zealand Company in 1842. The borough returns one member to the house of representatives, and its local affairs are administered by a mayor and council.  NELSONVILLE, a city of Athens county, Ohio, U.S.A., on the Hocking river, 62 m. S.E. of Columbus. Pop.(1890) 4558, (1900) 5421, including 328 foreign-born and 204 negroes; (1910) 6082. Nelsonville is served by the Hocking Valley railway. The city is in one of the most productive coal sections of the state; there are large quantities of clay in the vicinity; and the principal industries are the mining and shipping of coal and the manufacture of fire-clay products. Nelsonville was settled in 1818 and was incorporated in 1838; it was named in honour of Elisha Nelson, who built the first house here.

  NEMATODA, in zoology, a group of worms. The name Nematoda (Gr. , thread, and  , form) was first introduced by Rudolphi, but the group had been previously recognized as distinct by Zeder under the name Ascarides. They are now by

many systematists united with the Acanthocephala and the Nematomorpha to form the group Nemathelminthes.

The Nematoda possess an elongated and thread-like form (see fig. 1), varying in length from a few lines up to several feet. The body is covered externally by a chitinous cuticle which is a product of the subjacent epidermic layer in which no cell limits can be detected though nuclei are scattered through it. The cuticle is frequently prolonged into spines and papillae, which are especially developed at the anterior end of the body. The mouth opens at one extremity of the body and the anus at or near the other. Beneath the epidermis is a longitudinal layer of muscle-fibres which are separated into four distinct groups by the dorsal, ventral and lateral areas; these are occupied by a continuation of the epidermic layer; in the lateral areas run two thin-walled tubes with clear contents, which unite in the anterior part of the body and open by a pore situated on the ventral surface usually about a quarter or a third of the body length from the anterior end. These vessels are the nitrogenous excretory organs. The body-cavity is largely occupied by processes from the large muscle cells of the skin. These processes stretch across the body cavity to be inserted in the dorsal and ventral middle lines.

The body-cavity also contains the so-called phagocytic organs. These consist of enormous cells with nuclei so large as to be in some cases just visible to the naked eye. These cells are disposed in pairs, though the members of each pair are not always at the same level. The number of cells is not large (some 2 to 8), and as a rule they lie along the lateral lines. In some species (Ascaris decipiens) the giant cell is replaced by an irregular mass of protoplasm containing a number of small nuclei. Such a plasmodium bears, on its periphery, groups of rounded projections of protoplasm termed end-organs. Similarly the giant cells are produced at their periphery into a number of branching processes which bear similar end-organs on their surface and in some cases terminate in them. These end-organs are the active agents in taking up foreign granules, or bacteria, which may have found their way into the fluid of the body-cavity. From the shape and position of the phagocytic organs it is obvious that they form admirable strainers through which the fluid of the body-cavity filters (figs. 2, 3).

The alimentary tract consists of a straight tube running from the mouth to the anus without any convolutions; it is separable into three divisions: (1) a muscular oesophagus, which is often provided with cuticular teeth; (2) a cellular intestine; and (3) a short terminal rectum surrounded by muscular fibres. Neither here nor elsewhere are cilia found at any period of development.

A nervous system has been shown to exist in many species, and consists of a perioesophageal ring giving off usually six nerves which run forwards and backwards along the lateral and median lines; these are connected by numerous fine, circular threads in the sub-cuticle. Some of the free-living forms possess eye specks. The sexes are distinct (with the exception of a few forms that are hermaphrodite), and the male is always smaller than the female. The generative organs consist of one or two tubes, in the upper<section end="Nematoda" />