TUNGUS. 534 TUNING. the Golds of the lower Amur and the Ussuri, the Oroches on the coast, and the Daurians, or Solon-JJaurs, mixed with Mongols in Kulja; and the maritime Tungus or Lamiits of the shores of the Sea of Okhotsk. Among some of the Tungus Shamanism of a primitive sort prevails. The influence of the Russians, whicB began in the middle of the seventeenth century, is felt chiefly in the social life of the people. The Golds of the Amur, who have long been under the inlluence of China, have developed an exceedingly interesting ornamental art. They show considerable capacity for civilization. The Jlanchus are being more and more absorbed by the Chinese, whom their ancestors once con- quered. The Tungus generally are of medium height, but the Manchus are often very tall. The skull-form tends to be mesocephalic. Con- sult: Iliekisch, Die Tungusen (Saint Petersburg, 1879) ; Schrenck, Reisen und Forschunfjen im Amurlandc (ib., 1881-91) ; Castren, Grunckuge cincr tiingufiischen Sprachlehre (ib., 1856). TUNGTJSKA, tun-goo'sl<i4. A name given to each of the three large eastern tributaries of the Yenisei River in Siberia. They are distinguished as the Upper, Middle, and Lower Tunguska. The first is more commonly known as the An- gara (q.v.), the second as the Stony Tunguska, and the third as the Lower Tunguska. TUNGUSKA, Lower. The northernmost of the three chief tributaries of the Yenisei River in Siberia (Map: Asia, K 2). It rises on the Vitim Plateau in the Government of Irkutsk, about 200 miles northwest of Lake Baikal, and flows first north, then northwest, joining the Yenisei near Turukhansk, not far from the Arctic Circle, after a course of 1600 miles. Its upper course flows between low banks covered with pine forests, but lower down the banks become higher and rocky, and the river penetrates a range of mountains in a scries of rapids. The river is navigable about 450 miles, but it is frozen in its lower course for seven months in the year. The ice here blocks the upper w-aters in the spring, causing extensive inundations. The Low- er Tunguska comes within 14 miles of the Lena River. TUNICA, toS-ne'ka. A Korth American In- dian linguistic stock. See TonIca. TUNIC AT A (Lat. nom. pi. of tunicatus, p. p. of tunicare, to clothe with a tunic, from tunica, tunic) . The single class of the Urochorda containing small marine animals inclosed in a soft elastic tunic, which opens by two aper- tures (oral and anal), and contains tunicin, a substance resembling cellulose. The tunic is usu- ally thick, tough, and leathery, but may be very thin and delicate, especially in some of the smaller forms. The mouth, supplied with tactile organs, opens into a capacious pharynx, which contracts abruptly into a narrow oesophagus, then expands into a stomach, followed by a more or less coiled intestine that terminates close to the atrial pore or orifice (the other opening in the tunic). The walls of the pharynx are per- forated by numerous slits, through which the water entering at the mouth passes out into the cavity of the tunic and thence escapes through the atrial pore, carrying with it the waste mat- ter, reproductive products, etc. The pharynx is thus an important respiratory organ and is corre- spondingly richly supplied with blood vessels. The heart is peculiar, in that it reverses its beating, pun}pii]g the blood in one direction for a time, then pausing and presently pumping the blood in the other direction for an e([ual length of time. The nervous system is greatly reduced, and sense organs, except those of touch, are gen- erally wanting. The muscular system is well developed in some forms, especially in the tunic, but in others it is reduced and serves chiefly for closing the oral and atrial pores. Reproduction is not only by eggs, but takes place in many forms also by budding. In size and color the tunicates offer the greatest possible diversity. The smallest forms arc, as individuals, only a few millimeters long, though the colonies which they C()iii|)Ose are often many inches in diameter. The largest individuals are six or eight inches high, though some forms are on stalks of much greater length. In color we find some species jet black and some pure white, and others fire red, but dull shades of greenish, grayish, or brownish are more com- mon. JIany of the free-swinnning forms are al- most transparent and nearly colorless. The number of species of tunicates is large and the classification has varied greatly with difl'erent writers. They are a comparatively well defined group and are now considered as a considerably degenerated offshoot of the branch from which the Chordata have arisen. (See AsciDiAN.) The tunicates may be conveniently divided into three orders, the Larvalia, the Thaliacea, and the Ascidiacea. The Larvalia are a very small group, containing only one family and few species, remarkable for their small size and free-swimming habits, and the retention throughout life of certain characters which in the other orders occur only temporarily during their development. These larval characters are especial- ly the tadpole form with a tail, the neiwe cord, and the persistent notochord or urochord. The Thaliacea are also free-swimming, but are much larger and more degenerate or specialized forms. There are three families, one of which contains the beautiful salpas (q.v.). The order Ascidiacea contains three suborders and a dozen or more families. One suborder is free-swimming like the salpas. and so is called the Salpiformes ; the second, called Compositte, contains fixed forms which multiply extensively by budding and thus form compound organisms, the in- dividuals of which are usually very small ; the third suborder, the Simpliees, are almost al- ways fixed individuals (see Ascidian) ; but in many cases large numbers of individuals are united by a common stolon from which they have arisen by budding, and these forms are sometimes known as social ascidians. The Sim- pliees are better known, popularly, than the other suborders, and many of them have popular names, as sea-pork, sea-peach, sea-potato, and sea-squirt. Consult Herdman. "Report on the Tunicata," in Ohnllenger Reports, vol. vi. (London, 1888). TUNING. The process of bringing into per- fect nnisical accord the strings, pipes or mem- branes which constitute tone-producing elements of the various musical instruments. As a rule the wind instnmicnts do not require special tun- in.ir. for their pitch is constant. Keyed instru- ments (the piano and organ) require only occa-
