1057 



THEMISTO. 



THIA. 



1058 



This species is generally considered to have been wall-known to 

 the ancients, and to be that noticed by Hippocrates and Aristotle : 

 these Thclphuiie are supposed to be the Heracleotic Crabs (at 'HpaK\e- 

 urixol KofKii-oi) of the latter (' Hist. Anim.,' iv. 2) ; and to be those 

 represented oil ancient medals. It burrows in the earth on the banks 

 of rivers. 



Ttielphtaa Jtutitlilii, reduced, a, external jaw-foot of some. 



2. Third joint of external jaw-feet nearly square, and giving inser- 

 tion to the succeeding joint towards the middle of its anterior 

 border. 



Ex. oscia dentata. Length about 2 inches. It inhabits the Antilles 

 nnd South America. 



Souia dentata, reduced one-third. 

 a, antennary region ; b, external jaw-foot. 



3. Third joint of the external jaw-feet having nearly the form of a 

 reversed triangle, and giving insertion to the succeeding joint 

 by its external angle. 



Ex. Trichodactyliu quadratut. Length about an inch. It is a native 

 of Brazil. 



THEMISTO (Ouerin), a genus of Amphipodous Crustacea. 



THENARDITE, Anhydrout Sulphate of .SWa, a Mineral, occurring 

 crystallised. Primary form a right rhombic prism. Cleavage parallel 

 to the primary planes. Colour white or reddish. Transparent ; trans- 

 lucent; opaque. Soluble in water; effloresces on the surface. Specific 

 gravity 2-73. 



It occurs in crystalline coatings at the bottom of soma lakes, at a 

 place called Las Salinas Espartinas, about five leagues from Madrid. 

 It is used in the preparation of carbonate of soda. According to the 

 analysis of Casaseca it in composed of 



Sulphate of Soda S9'78 



Carbonate of Soda .... 22 



100 



THENUS. [SCTLLARIDA] 



THEOBKO'MA (from i6t and Pp&pa, the food of gods), a genus of 

 Plants belonging to the natural order Sterculiacea, the species of which 

 yield the Cocoa of commerce. They are trees with large simple leaves 

 and with the flowers in clusters. The calyx is composed of 5 sepals ; 

 the petals are 5, lengthened into a strap-like form at the apex ; the 

 stamens mre 5, each with double anthers and a horn-like appendage 

 between eaoh filament ; the style is filiform, with a 5-parted stigma ; 

 fruit a 5-celled capsule without valves; seeds imbedded in a soft 

 pulp ; no albumen, and thick oily wrinkled cotyledons. 



T. Cocoa, Common Cacao, or Chocolate Nut-Tree, has entire, elliptic, 



SAT. HUT. PIT. VOL. IV. 



oblong, acuminate, quite smooth leaves, and oblong smooth fruit 

 This tree is indigenous in South America, and is generally found at 

 a height of 600 feet above the level of the sea. It is however exten- 

 sively cultivated in the West Indies, and in the tropical parts of Asia 

 and Africa. The Mexicans call the tree Chocolalt, hence our word 

 Chocolate for the prepared seeds. The capsules of the fruit are large, 

 and contain each about 25 seeds : the pulp in which these are enveloped 

 has a sweet and not unpleasant taste, and is frequently eaten where 

 the tree is grown. The trees are evergreens, and bear fruit and flowers 

 all the year through, but the usual times for gathering the fruit are in 

 June and December. Tho cotyledons of the seeds contain a large 

 quantity of oily albumen, which has an agreeable flavour, and on this 

 account they are not only used as a principal article of diet by the 

 natives of the countries in which they grow, but are now used for the 

 same purpose throughout the civilised world. The composition of 

 these seeds, in which amylaceous matter is combined with oil, and a 

 principle, called Theobromine, similar in its constitution to Thein and 

 Caffein, is well adapted, when combined with sugar, to form a valuable 

 article of diet. [Fooa] 



The oil contained in the seeds is sometime? obtained separately, and 

 called cocoa-butter. It may be obtained easily by expression, especially 

 if hot-water is added. It is said to be very nutritive, and to act as an 

 anodyne. It is particularly recommended for making ointments. (Ersch 

 and Gruber, ' Allgem. Encycl.,' art. Cacao.) 



There are several other species of Theobroma, yielding seeds possessing 

 the properties of the above, but they are not cultivated or employed 

 to the same extent. They are all of them natives of South America, 

 and used by the inhabitants where they grow as food. T. Guazuma of 

 Linnaeus, the Bastard Cedar, or Orme d'Amerique, now the G. ulmi- 

 folia, is a native of the West Indies, and is a handsome tree resembling 

 the elm. 



THEONIA. [MILLEPOBIDA] 



THEONO'A, a genus of Fossil Zoophyta. 



THEOPHRASTA, a genus of Plants dedicated to Theophrastus. 

 It was originally called Ereaia by Plumier, but afterwards altered by 

 Liunccus. T. Jutsieui belongs to the natural order Myrsinacece, and is a 

 small tree with a simple unbranchedstem, furnished with a tuft of long 

 evergreen leaves at top, giving it a resemblance to a palm-tree. The 

 flowers are of a white colour, and are arranged on terminal racemes, 

 which are very short, and hidden amongst the leaves of the plant. 

 The calyx is campanulate and cartilaginous. The corolla is also 

 campanula^, with a short tube, and has a dilated throat, girded by 

 an elevated angularly-lobed, fleshy, arched ring : the limb is spreading. 

 The stamens are five, combined with the tube of the corolla ; anthers 

 horned. The fruit is a crustaceous spherical berry, about the size of 

 a crab-apple, with the seeds half immersed in the placenta. The T. 

 Jussieui is the only species. It is a native of the mountains of St. 

 Domingo, and is much cultivated on account of its long handsome 

 holly-like leaves. It may be propagated by cuttings, and grows well 

 in a soil of peat, loam, and sand. 



THERATES. [CTENOSTOMA.] 



THERIS'TICUS, a genus of Birds. 



THESPE'SIA (from ecmrcVios), a genus of Plants belonging to the 

 natural order Malvacece. The species are trees with large entire leaves. 

 The calyx is truncate, and girded by a 3-leaved deciduous involucel ; 

 the fruit is a capsule with 5 cells, and each cell is semi-parted, with 4 

 seeds at the base. 



T. populnea, Popular Thespesia, has roundish cordate pointed 

 5-7-veined leaves, with dot-like scales beneath, with the peduncles 

 equal in length to the petioles. This plant is a native of the East 

 Indies, Guinea, and the Society Islands ; and is known, where it grows 

 amongst British colonists, as the Umbrella-Tree. It attains a height 

 of about 40 feet, and has large yellow flowers with a dark-red centre. 

 In the tropics it has gained for itself a sacred regard, and is planted 

 about monasteries and convents ; hence the name Thespesia (divine). 

 There are two species, natives of South America : they are all trees, 

 with handsome showy flowers. 



THETIS, a genus of Fossil Shells. 



THIA, a genus of Crustacea. T. polita is a British species. It lives 

 buried in the sand at a small distance from the shore. The colour is 

 rosy. Length 10 lines. 



Thin pnlita. 



BY 



