USED IN NATURAL HISTORY. 



149 



TRAPE'ZIFORM. Shaped like a tra- 

 pezium. 



TRAPEZOID. ) In form of a trape- 



VRAPEZOIDAI.. zium. 

 ^RA'PPEAN. Relating to trap rocks. 

 TRA'VERTI N. fr. it. travertine. Lime- 

 stone deposited from water hold- 

 ing carbonate of lime in solution. 

 It is found in the sweet springs 

 of Virginia, and at the hot springs 

 of the Washita, in Arkansas, as 

 well as in many other places. 



TRE'MOLITE. A mineral, often of a 

 fibrous structure, generally con- 

 taining silica, magnesia, and car- 

 bonate of lime, originally found 

 in the valley of Tremola on St. 

 Gothard, 



TRENCHANT. Cutting. 



TRIADK'LPHOUS. fr. gr. treis, three ; 

 adelphia, brotherhood. In botany, 

 applied to the filaments of plants 

 which are combined into three 

 masses. 



TRIAKE'NIUM. A fruit consisting of 

 three achsenia or cells. 



TRIA'NDRIA. fr.gr. treis, three; aner, 

 stamen. Name of a class of 

 plants. 



TRIA'NDROUS. Having three sta- 

 mens. 



TRI'AS. fr.lat. tres, three. Synonym 

 of the triassic system of rocks, 

 consisting of the Bunter Sand- 

 stein, the Muschelkalk, and Keuper, 

 a group of sandy marls of varie- 

 gated colours. (p.49, Book viii^ 



TRIA'SSIC. Of the nature of trias. 



TRICHE'CHUS. fr. gr. trix, hair. Sys- 

 tematic name of the morse. 



TRICKO'TOMOTTS. fr. gr. trecha, in 

 three parts ; temno, to cut. In bo- 

 tany, applied to inflorescence and 

 branching, when the divisions oc- 

 cur in threes. 



TRICOC'COUS. fr. gr. treis, three; 

 kokkos, a seed. In botany, split- 

 ting into three indehiscent carpels. 



TRICO'LOR. Lat. Three-coloured. 



TRICO'RNIS. fr. lat. trcs, three ; cor- 

 nu, horn. Three-horned. 



TRICU'SPIB. fr. lat. tres, three ; cug- 



13 



312 



pis, a point having three points. 

 The three valves situate in the 

 right auriculo-ventricular opening 

 of the heart are thus named. 



TRicuspiDATE.-Having three points. 



TRIDA'CHTA.-^A genus of mollusks of 

 the family of chamacea. 



TRIDA'CTYLOUS. Having three toes 

 or fingers. 



TRIDA'CTYLUS. fr. gr. treis, three ; 

 daktulos, a finger. Three-fingered. 



TRIDENTA'TA. Lat. Three-toothed ; 

 having three teeth. 



TRIE'NNIAI. Every three years. 



TRIFA'RIOUS. Arranged in triple 

 ranks. 



TRI'FID. Three-cleft: divided in 

 three. 



TRIG O'N AI.. Th ree-cornered . 



TRIGONA'LIS. Lat. fr. gr. treis, three ; 

 gonia, angle. Having three an- 

 gles or corners. 



TRIGO'NIA. fr. gr. trigonos, three- 

 cornered. A genus of bivalve 

 mollusks most of which are ex- 

 tinct. 



TRIGONOCE'PHALI. Lrat. plur. of tri- 

 gonocephalus. 



TRI'GONOCE'PHALUS. fr. gr. treis, 

 three; gonos, an angle; kephale, 

 head. A genus of very venom- 

 ous serpents. Trigonoce'phalus Ian- 

 ceola'tus. Lance-head viper. 



TRIGO'NITLA. Lat. Having three 

 little angles. 



TRIGY'NIA. fr. gr. treis, three ; gttne, 

 pistil. Name of an order of plants. 



TRI'IO BATE. -Formed of three lobes; 

 a form of leaf. (fig. 30, p. 37. 

 Book vii). 



TRI'LOBED. fr. lat. tres, three ; lobus, 

 lobe. Formed of three lobes. 



TRI'LOBITE. fr. lat. tres, three ; lobus, 

 lobe. A fossil crustacean, (fig. 4, 

 p. 28, Book viii). 



TRILO'CULAR. Having three cells. 



THIME'RANS. fr. gr. treis, three; me- 

 ros, a joint. A division of coleop 

 terous insects whose tarsi consist 

 of three joints. 



TRI'MEROUS. Consisting of three 

 parts. 



