tunic (tunik)

[ or Tunic or Chiton of Ionian form (over it is girded the Dionysiac nebris or fawn-skin), from a Greek amphora of the 4th century B. C., found at Perugia. (From "Monuu. ment i dell' Instituto.") ancient Roman senator a broad vertical stripe of purple (called lat us clavus ) was woven; the equites wore two narrow parallel stripes (called angusti clavi ) extending from the shoulders to the bottom of the tunic. Hence the terms lati clavi i and an gust i clavi i applied to persons of these orders. See also cut under stola. Tunick or Tunicat, a Jerkin, Jacket, or sleevele coat, formerly worn by Princes. Blount , Glo ographia (1670). 2. At the present time, a garment generally loose, but gathered or girded at the waist, worn by women, usually an outer garment; a sort of wrap or coat for street wear. Her Majesty wore a white satin petticoat, over which was a silver llama tunic , trimmed with silver and white blonde lace. First Year of a Silken Reign , p. 230. 3. Eccles., a vestment worn over the alb in the Roman Catholic Church and in some Anglican churches by the subdeacon or epistler at the celebration of the ma or holy communion. It is similar in shape and color to the dalmatic, but sometimes smaller and with le ornamentation. The bishop's tunic is worn under the dalmatic, and is shorter than the subdeacon's. See tunicle. 4. A military surcoat.-5. In the British army, the ordinary fatigue-coat: applied usually to the coat of a private, but sometimes to that of an officer. [Colloq.] "Please show me your Victoria Cro ." "It's on my tunic, and that 's in my quarters in camp." J. H. Ewing , Story of a Short Life, vii. 6. A natural covering; an integument. Specifi. cally-(a) In an at., a covering or investing part; a tunicle; a coat, as of the or an artery. tunica. (b) In zool., one eyeball the stomach the ervering of an ascidian. See Tunic at a (with cut), and cut under Ascidia. (c) In bot., any loose membranous skin not formed from epidermis the skin of a seed; also, the peridium of certain fungi. - Albugineous tunic. Same as albuginea.- Arachnoid tunic. Same as arachnoid, 3. Inner tunic, in bot., a membrane, more or le colored, which surrounds the nucleus or hymenium in the genus Verruca ria, situated immediately beneath the perithecium. Leighton, Brit. Lichens. - Ruyschian tunic. Same as cho rio cap ill aris. - Talaric tunic. See talaric, and Ionic chiton, under chiton.-Vaginal tunic. See vaginal and eyel, 1. tunica (tū'ni-kä), n.; pl. tunica (-sē). [NL., 6530 -Tunica a rach no idea. (a) The arachnoid membrane, a thin membrane forming one of the coverings of the brain and spinal cord. (b) One of the layers of the choroid coat of the eye.-Tunica cho rio cap ill aris. Same as choriocapil laris. Tunica conjunctiva. Same as conjunctiva, 1.Tunica cornea pellucid a. Same as cornea, 1. -Tunica granulosa, the granular lining of the cavity of a Graafian muscular is mucose, a thin and at places incomplete layer of smooth muscle-fibers in the mucous membrane of the alimentary canal. Also called simply muscular is mu cose. propria, in an at.: proper coat of some structure, as an artery; the layer which specially constitutes such a structure, as distinguished from other layers which may form a part of it by investing or lining it. The tunica propria of the spleen is a strong elastic connective-ti ue coat lying immediately beneath the serous coat; that of the testis is defined under tunica vaginal is testis. (b) Specifically, the membrane lining the bony labyrinth of the ear; the walls of the membranous labyrinth. - Tunica reflex a, the outer wall of the tunica vaginal is testis. Tunica Ruyschiana. Same as cho rio cap ill aris. -Tunica vaginal is oculi, a sheathing fascia which surrounds the optic nerve and part of the eyeball, formed of fascia. Tunica vaginal is testis, the serous investment of the testicle, formed of a pouch or proce of the peritoneum, usually a shut sac: it has two walls, the tunica propria, upon the testis itself, and the tunica reflex a, separated from this by the cavity. - Tunica vasculosa Halleri. Same as cho rio cap ill aris. - Tunica vasculosa testis, the pia mater of the testicle, a vascular layer underlying the tunica albuginea. Tunica intima. Same as intima. - Tunica tunicary (tūʼni-kā-ri), n.; pl. tun i caries (-riz). [ Tunic at a (tū-ni-kāʼtä), n. pl. [NL., neut. pl. of tunic at us, clothed with a tunic: see tunicate.] A cla , supercla , or phylum of animals intermediate between and connecting the invertebrates with the true vertebrates, now made a prime division of chordate animals (see Chor data ); the ascidians, tun i caries, or sea-squirts. The evidence of vertebrate affinity or character chiefly in the larval state, when there is a sort of notochord, the urochord (see Urochord a ), which in one group persists in the adult (see Appendicu lariida). The tunicates are so called from the thick, tough, leathery integument or tunic, the name having been given by Lamarck in 1816 to the forms then known, and the cla having been placed in his system between the worms and the radiates. The tunicates had before been regarded as polyps or even as sponges; with Cuvier they formed a division ( Nuda ) of mollusks; afterward and for many years they were considered as molluscoids, and a ociated with or approximated to the brachiopods and polyzoans. The discovery of the urochord by Kowalevsky in 1866 gave the first evidence of their proper position among chordate animals, and consequently of their vertebrate affini ty. They were thereupon regarded as the "ancestors" of the verte brates, of which, however, they appear rather to represent a degenerate or retrograde side-shoot. Thede velopmental history is intricate and perplexing. Alternation of generation has been determined for the whole group, and some members of it occur under two distinct forms. IMG:content-1062.jpg:[ocr errors] 1c IMG:content-1063.jpg:[ocr errors] IMG:content-1064.jpg:[ocr errors] IMG:content-1065.jpg:[ocr errors] Phallus i a mentula, one of the Tunic at a, the test removed; the dinal section. cut is in effect a longitu ganglion; c, circlet of a, oral aperture; tentacles; d, branchial sac, the three rows of marks at its upper part indicating the stigmata; geal opening; g, stom ach; h, intestine;, anus; &, atrium; 7, atrial orifice; m, endostyle; One of the most remarkable pecu-e, languets; f, esopha liarities of Tunic at a is the presence in the integument of tunicin, a kind of animal cellulose-cellulose hav ing been supposed to be peculiar n, heart. to plants. Tunicates are very di imilar to one another in outward appearance, though they conform to a type of structure most parts of which can be clearly homologized with those of vertebrates. An ord i nary simple ascidian resembles a leathern bottle fixed at the base, and provided with two openings, through one of which water is indrawn, and through the other of which it can be expelled with some force when the animal contracts, whence the name sea- squirt; other fanciful names are sea - pear, sea - peach, sea - pork, and sea - potato. Other tunicates, also fixed, are social, aggregate, or colonial; some are free-swimming, or fixed and free at different stages of their development, and of the free forms some are simple and others are linked in chains. The salps and pyrosomes are phosphorescent. All tunicates are marine; most live on the shore or surface, but some at great depths. Their cla ification has been almost as changeable as their location in the system. The arrangement of H. Milne Edwards (1826, and long current with little modification) has been entirely remodeled. Ac cording to the latest views, Tunic at a rank as a cla divided into three orders: ( a ) Larval i a, tailed when adult, represented by the family Appendiculariidæ (see cut under Appendicular i a ); (b) Thaliacea, free-swimming, simple or compound, without a tail in the adult, and either cyclomyarian ( Doliolidæ ) or hemimyarian ( Salpidæ and Octacnemide ) (see cuts under Doliolidæ and Salpa ); and (c) Ascidiacea, of which there are three groups or suborders (1) Salp i formes, resembling salps in being free swimming, colonial, and luminous, with one family, Py rosomatidæ; (2) Compos itæ, fixed, reproducing by gemmation and so forming compound organisms, with seven families, of which Botryllidæ is the best-known, a member of it having been described in 1756; and (3) Simplices, fixed (exceptionally free) and solitary (rarely social - that is, imperfectly composite), with four families, Molgulidæ, Cynthiidæ, Ascidiida, and Clavellinida. The last named are the social ascidians; the second and third families are each divided into subfamilies ranked as families by some writers, and are also the largest families, represented by the numerous genera and species which come most frequently under observation, and to which the common name ascidian is specially pertinent. (See cuts under As cidia and gastrulation.) A former broader arrangement, which ignored the peculiarities of the Larval i a, was into tius orders, by means of which the sales and the doliolids on the one hand were contrasted with all other tunicates on the other; and each of these orders had a number of different names. Also called Ascidioida. tunicate (tū'ni-kat), a. andn. [L. tunic at us, pp. of tunic are, nicare, clothe with a tunic, IMG:content-1066.jpg:[graphic] like funnels. II. n. 11. A tunic. Blount .-2. An ascidian, tunicary, or sea-squirt; any member of the Tunic at a .