Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/631

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TETRADECARHOMBIS, in natural hiftory, the name of a genus of foffils, of the clafs of the felenitse. The word is derived from the Greek tet§«V, four, &*»?, ten, and gV&Jj a rhomboidal figure^ and exprefles a rhomboidal body confuting of fourteen planes.

The characters of this genus are, that the bodies of it are exactly of the fame form with the common felenitae ; but that in thcie each of the end planes is divided into two j and there are by this means eight of thefe planes, inftead of four. Hill's Hift. of Foil", p. 120. See the article Selenites. Of this genus there are only three known fpecies. i. A thin pellucid one, with tranfverfe filaments j which is frequent in the clay-pits of Northampton! hire, and fome other counties. 2. A dull thicker kind, with very flender tranfverfe filaments ; this is a very rare fpecies, and found as far as is yet known only in Leicefterihire in the yellow brick clay, and at final! depths. And, 3. A large fcaly kind, confiderably long, and of a very rough iurfacc ; this is found in Yorktture, and that fometimes looie on the fides of the hills, but more frequently buried in the ft rata of clay, ffiffs " HMh of Foil', p. 133, 174, 135* See Tab. of Fulfils, Clafs 2.

TElKAiJYNAMiA, in botany, a clafs of plants, whofe flowers have four of their ftamina of more efficacy than the reft : Thefe are always known by having the four efficacious ftamina longer than the reft.

The word is formed of the Greek wrg*\, four, and oWj*k, power. Of this clafs of plants are fcurvy-grafs, muftard, ra- difh, &c. See Tab. 1. of Botany, Clafs 1. The Tetr adynamia of Linnaeus include thofe called by Tour- nefort critciformes, and by Ray Jiliquoja, and jilicubja. The general characters of the clafs are thefe : The perianthium is of an oblong figure, and is compofed of four leaves, which are oval, oblong, hollow, obtufe, and con- verging toward one another, and are gibbous at the bale; thefe all fall off with the flower, and ftand in pairs ; the op- pofite ones being always equal in length, this cup is properly the nectarium of the plant, and it is on this occalion that it is gibbous at the bafe. The flower is of that kind, called by Tournefort, cruciform ; it confifts of four equal petals, which have ungues of the length of the cup, erect, and fiat ; the petals are broad at the top, and obtufe, and fcarce touch one another at the fides ; and the infertion of the petals and of the ftamina is in the fame place.

The ftamina are fix fubulated erect filaments, the two oppo- fite ones are of the length of the cup, the other four are fomething longer, and are of a lefs length however than the petals. The anthers are oblong and pointed, thick at the bafe and erect, with apices bending fide ways. The nectari- ferous gland in the different genera of this clafs is differently fituated. It ufually however is found near the ftamina, and moil frequently of all is affixed to fome fhort filaments, and ftands near their bafe. Two of the ftamina are often curved^ that they may not prefs upon this gland ; and it is often ow- ing to this, that two are ihorter than the reft. The germen of the piftil is placed above the receptacle, and is every day in its growth raifed higher and higher. The ftyle is fome- times wanting, but in fuch plants as have it, it is of the length of the longer ftamina. The ftigma is always ob- tufe.

The fruit or capfule is always a bivalve pod, which often con- tains two cells ; this, when ripe, opens by fplitting from the apex to the bafe, and it has always a little membranous fub- ftance ferving within as a feptem, when the pod is bilocular; this ftands out beyond the apex, and is the rudiments of what was before the ftyle. The feeds are roundifh, and the pod ufually narrow and oblong.

This is a very natural clafs of plants, and has been received as fuch under whatever name by all the fyftematical writers in botany.

The plants of this clafs are generally fuppofed to be all anti- fcorbutics. This clafs of plants is naturally fubdivided into two feries : The one containing the filiculofe plants, and the Other the filiquofe. Thefirithave albort pod, the others a lung and flender one. The firft pods ufually have more of the remains of the ftyle than the others. Lmnai Gen. Plant, p. 309.

TETRAETERIS, TiTgaiTwgi?, in the Athenian chronology, a cycle of four years ; for which fee Potter, Archzeul. Grcec. 1.2. c. 26. T.I. p. 459, feq.

TETRAGONIA, in botany, the name given by Linnaeus to a genus of plants called by others Tetragonocarpos. The cha- racters are thefe ; The cup is compofed of four oval coloured leaves, curled at their edges, and remaining after the flower is fallen. There are no petals. The ftamina are twenty ca- pillary filaments, ihorter than the cup. The antherse are fhort, and incumbent. The gerinen of the piftil is roundifh, qua- drangular, and placed under the receptacle. The ftylcs are four, fubulated, crooked, and of the length of the ftamina. The ftigmata are longitudinal and hoary. The fruit is a co- riaceous cruft, formed into a kind of fquare figure, by four longitudinal alas. The feed is Angle, offeous, and contains fou/ cells, with oblong nuclei. Linnai Gen. Plant, p. 249.

TETRANDRIA, in botany, a clafs of plants which have her- maphrodite flowers, with four ftamina or male parts in each. See Tab. 1. of Botany, Clafs 1.

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The word is formed of the Greek ,^ e c;, four times, and A.»f, male. Of this clafs of plants are the teafel, madder, plantane, C3V.

TETRANGURIA, in botany, a name ufed by fome authors for the citrul, a plant of the gourd kind, whole feeds are ufed in medicine. Cbabraus, 133.

T£ TK.AO, in the Linmean lyftem of zoology, the name of a genus of birds of the order of the gallinse ; the diftinguifhing characters of which are, that the feet have each four toes, and the eyelids are naked and full of flefhy tubercles. Of this genus are the pheafant, partridge, quail, £SV. Linnet Syft. Nat. p. 48.

TitRftb, is alfo ufed for a large bird of the gallinaceous kind, whereof there are two fpecies, the one larger, and the other lelTer ; they are called alfo by authors, the urogatius major, and ?mnor.

The larger is common in Italy, and on the Alps ; fee the article U roc alius. The lell'er is common in fome parts of England, and is called the black game, or the greufe. Kaf% Ornithol. p. 123. See the article Grouse.

TETRAPHOE, in botany, a name given by the people of Guiney to a plant, which they give in decoction as a cure for fluxes. This plant grows alio in Malabar, where they ufe the roots boiled in whey in the piles ; and in the colic they give the root in powder, about a fcrnple for a dofe. It is called in this latter place wellia cadavalli, and by Petiver xanthium makbaricum capitutis lanugnufn. The italics of it are woody and hoary, elpecially about the tops. Its leaves itand by pairs on ihort foot-ftalks, and while young they are hoary underneath, with a very (bit and velvety down ; the o- thers are rough like the (potted lungwort, but feldom are fo large. The flowers grow in fpikes, and conliil each of fine green leaves filled with fcarlet filaments : After thefe the fruit ripens, and is a fort of woolly bur covered with loft and hook- ed prickles, very like the common Engliih burdock, but not of a third part of the bignefs. Phil, l'ranf. N°. 232.

TETRAPYRAMlDIA, in natural hiftory, the name of a ge- nus of fpars. The word is derived from the Greek Tir^t, four, and 71-1/^1;, a pyramid.

The bodies of this genus are fpars influenced in their fhape by an admixture of particles of tin ; and are found in form of broad-bottomed pyramids of four fides. Of this genus there is only one known fpecies, which is ufu- ally of a brownilh colour, and is found in Saxony ; as alfo in Devonfhire, Cornwal, and other counties of England, where there is tin. Hill's Hift. of Foil. p. 378.

TETRASTCECHON, in botany, a term often ufed by the the Greek writers, and generally mifunderftood by thofe who copy their accounts. Pliny has made an error in the defcrip- tion of the euonymus, which has confounded two different flrrubs together ever fince, by miftaking the fenfe of this word, ufed by Theophraltus in his account of it. He fays, that the fruit is divided within into four orders or feries of feeds; this he exprefles by the word Tetrajicecbon, which Pliny fuppofing to be the fame with the word titraganon, has tranilated into granum auadranguta figura. But this is by no means the fenfe of the word which was ufed by the Greeks, to exprefs, that a thing had rliufkt Ta&K, four rows, orders, or feries of feeds in it : Nor does it at all exprefs the feed's being fquare, much lefs its being fingle ; for the original derivation of the word was from the term xttTa ro^', ufed in dances. Thefe were compofed of feveral feries of perfons, called r°>x",Jta?c/ji; and every ftcechon confifted of ieveral perfons, who all moved together. It is plain from this, that Tetrajicecbon could not fignify a fruit's having fingle fquare feeds, but muft mean that it had four ftcechi or orders of feeds in it ; fuch was the euonymus of the Greeks, which had a pod like that of fefamum to con- tain them ; and had flowers of an offenlive fmell, like that of corrupted blood. Thefe are all characters fo very different from that of our euonymus or fufanus, that it never would have been fuppofed by any perfon that they meant the fame plant that we do by that name, had not Pliny led the world on to that opinion Dy his falfe and fcarce intelligible tranfla- tion of the words of Theophraltus.

TETRATONON, in mulic, the fuperfluous fifth is fometimes thus called, as containing four tones. BroJJard.

TETRAX, in zoology, the name of a bird of the gallinaceous kind, called by fome authors anas campejlris, or the field- duck ; and by others the canna.

It is a very common bird in France, where it is called came patriere, and feems indeed peculiar to that country ; it is not called anas from any refemblance it has to the duck, or any other water-fowl, in its make or ftructure ; but from its fitting on the ground, juft as the duck does on the water. It is of the fize of a pheafant, and has a beak like that of the common hen. It is taken with nets, as the partridge : It runs very fwiftly, and, like the buftard, has no hinder toes ; and it feems properly a bird of that kind. Its belly is white, and its back is variegated with grey, red, and black. It feeds on vegetables, and on fmall infects. Bcllmius de Avibus.

TETRASARIUS, a word ufed by fome of the medical writers, to exprefs half an ounce.

TETREUMA,