TULLOCH
1950
TUNIS
as poplar. It is one of the most magnificent forest-trees of the United States, with a noble shaft, great crown, broad and lobed leaves and tulip-like flowers. It is the source of the so-called poplar-lumber of commerce; from the color of its wood it is called whitewood; and in some localities it goes by the name of yellow poplar. The tree sometimes reaches a height of 190 feet, the ordinary height being 70 to 100 feet. It is rare in New England and west of the Mississippi River, but is found as far south as Alabama and Georgia. It grows rabidly and is hardy. Always attractive, in its time of bloom it is of much charm, bearing a wealth of erect, cup-shaped, yellow-green blossoms.
Tulloch (t&l'Uik), John, D.D., a Scottish theologian and author, principal of St. Andrews University, was born in Perthshire, June i, 1823, and died at Torquay, Devon, Feb. 13, 1886. He was educated at Edinburgh and in Germany, and was one of the leaders of liberal thought in theology in his time. His writings embrace a Burnett prize-essay entitled Theism the Witness of Keason and Nature to an All-Wise and Beneficent Creator; Leaders of the Reformation;^ English Puritanism and its Leaders; Rational Theology and Christian Philosophy in England in the ifth Century; The Christ of the Gospels and the Christ of Modern Criticism; Modern Theories in Philosophy and Religion; Movements in Religwus Thought in Britain in the i$th Century; volumes of sermons" and an inspiring book for young people, entitled Beginning Life. He visited the United States in 1874. See Memoirs by Mrs, Oliphant.
Tul'sa, Okla., county-seatjof Tulsa County, is in a fine agricultural section, which also is a coal, oil and gas belt. Shale, fire-clay, limestone and sandstone are in the vicinity. The city has excellent public schools, with free kindergartens, a business college and the Presbyterian State University. It is a city of good homes and churches. Tulsa has an excellent sewerage-system and the service of five railroads. Population 18,182.
Tum'bleweed, the popular name of various annual plants which have a bushy, branching habit and become more or less globular in outline by the curving of the branches Being shallow-rooted, in light soil they are caught by the wind and tumbled along, sometimes being carried for many miles and scattering their seeds by the way. They belong to the prairies and great plains of this and other countries. One of the most common of the tumbleweeds has recently been imported into this country under the misleading name of Russian thistle. It is not a thistle, but a prickly member of the goosefoot family (Salsola kali tragus). It first appeared on the plains of Dakota, and has spread extensively.
Tu'nicates, an interesting group of marine animals, surrounded by a tunic from which their name is derived. They embrace animals called sea-squirts on account of their ejecting little ^ jets of water from their terminal openings when irritated. They formerly were classified with worms or between the worms and the mollusks. In 1866, however, Kovalevsky, by observing their development, showed that in early stages they come near the structure of tadpole or of frog. Moreover, the steps in their development were shown to agree fully with those of the lowest recognized vertebrate, Amphioxus. The adult animals are fixed or sessile, The laryse are free-swimming and, in some particulars, on a higher plane than the adults. They, for example, have a gristly rod or notochord in the back of the body and, above this, a nerve-cord in the same position as in vertebrated animals. They also possess gill-clefts. The notochord and dorsal nerve-cord disappear in the adult, but their presence in the larva makes it necessary to advance the tunicates into the vertebrated group, and it is now recognized that the possession of a notochord, a dorsal nerve-cord and gill-clefts marks the vertebrated animals and distinguishes them from all others. The work of Kovalevsky was epoch-making, because it broke down the supposed barrier between vertebrates and invertebrates, and opened the way for considering their affinities in an unbiased spirit. The tunicates are ovoid or barrel-shaped animals attached at one end to stones, weeds or other objects. The free end has two openings through one of which water enters and> after circulating through the gills, passes out of the other. They afford an illustration of degeneration in development. When free-swimming in their youth, they are on a higher level but soon become attached and, losing some of their organs, undergo retrograde development. See VERTEBRATES.
Tu'nis, once an independent state in what was called Barbary (q. -y.), is a French protectorate in Africa. It is bounded on the north and east bv- the Mediterranean, on the south by Tripoli and the Sahara and on the west by Algeria, It is 440 miles long from north to south and 115 wide, covering 64,600 square miles, Missouri or Washington (state) being only about 5,000 miles larger, and has a population of 1,900,-ooo or less than that of Chicago. The coast is irregular, and there is only one river, but there are many salt-marshes. Capes Blanco and Bon on the northern coast are Africa's farthest north. The northwest is mountainous, some peaks rising 5,000 feet, the south a steppe. ^ The country is fertile, the mountains being covered with great forests of oak and barley, figs, maize, olives, oranges and wheat being
