THF.. 'A. 



THKLPHUSID.E. 



nodding. This species it figured by Or. Lettaoui in hit account of 

 the tea-plant, t 1, and by Sir W. J. Hooker, ' Dot Mag.,' t 3148, 

 and in Loddiges' ' Bot Cab.,' t 227, all from plants which have 

 flowered in this country. Ktompfer supplied a very good figure, 

 ' Amoco. Exot.,' p. 607, from a Japanese plant. This species is found 

 both in China and Japan, and is supposed to be the species which 

 yields the green tea of commerce. It has been long introduced into 

 this country ; having been first sent from Japan in 1687 to the Cape 

 of Good Hope, and thence into Europe. 



T. Itohti is a smaller plant than T. viridii : its branches are stiff 

 and straight, its stem erect, the leaves not above half or two thirds of 

 tha size of tho former species, elliptical oblong, perfectly flat, more 

 coriaceous, of a dark green colour, with small and even serratures ; 

 they are numerous, and have in their axils two or three flowers, of 5 

 sepals and 5 petals, these are smaller and have a slight fragrance, and 

 flower later in the season than T. viridit. The plant ii much more 

 Under than the green tea-plant, and unable to stand the cold of an 

 English climate. It is supposed by some to yield the leaves which 

 are converted into black tea, and, notwithstanding contrary state- 

 ments, leaves similar to those of this plant may be recognised on 

 infu.iin; and spreading out tho leaves of some of the black teas of 

 commerce. [TEBSSTRuJli AOE.K.] A variety of this is sometimes called 

 T.tiricla. It is figured by Lettsom, ed. 2, p. 41, who considers it only 

 a variety of the former. It is also figured by Loddiges, ' Bot Cab.,' 

 . who, as well as Sir W. J. Hooker and Dr. Itoyle, considers it to 

 be a distinct species. 



T. Auamctuii, the Assam Tea-Plant, which some years ago attracted 

 so much attention, seems to partake of the characters of both the fore- 

 going. The Calcutta Tea Committee say, in 1835, "We are now 

 enabled to state with certainty, that not only is it a genuine tea, but 

 that no doubt can be entertained of its being the identical tea of 

 China, which is the exclusive source of all the varieties nnd shades of 

 the tea of commerce." To this it may be replied, that there are con- 

 siderable doubts whether the teas of commerce are all derived from 

 one species of plant. Mr. Griffith says, in the size both of the plant 

 and of the leaves, as well as in the texture of these last, and in its 

 stations, the Assamese plant approaches to the green tea-plant of 

 China ; in its geographical distribution, so far as latitude is concerned, 

 it approaches to the black tea. The inflorescence of the Assamese 

 plant varies, but perhaps its usual state is to have the flowers solitary 

 in the axils of the leaves, but the number of flowers varies from one 

 to five. The plants introduced into this country have their leaves 

 much larger and thicker than those of the green tea-plant, and 

 Messrs. Loddiges find that it requires a much greater degree of heat, 

 in fact that of the hot-house, while the others are in the open air for 

 a great part of the year. 



Two other species, described by Lourciro, are little known, as T. 

 CocAtncAiiunuu, about eight feet high, having lanceolate leaves, flowers 

 of three to five sepals and five petals, solitary, terminal ; found wild 

 in the north of Cochin-China, where it is also cultivated, being used 

 medicinally by the natives as a diaphoretic. T. oltota is also a shrub 

 of eight feet high, found in the fields in the neighbourhood of Canton, 

 and named from its seeds yielding a large quantity of oil, which is 

 used for burning and as an article of diet. The leaves are lanceolate, 

 the flowers of six sepals and six petals, peduncles 3-flowered, axillary ; 

 fruit stated to be indehiscent, rather a berry than a capsule. [TEA, 

 in AHTS ASD Sc. Drv.) 



Til EGA (in Anatomy) is a term commonly applied to the strong 

 fibrous sheaths in which certain soft parts of the body are inclosed. 

 Thus the Tlicca vtrtebralit is the sheath of dura mater in which the 

 spinal cord is inclosed ; and the canals through which many of the 

 lonz tendons of the muscles of the band and foot run are called thecjo. 



The same term is employed in vegetable anatomy. It was applied 

 by Grew to that part of the stamen which contains the reproductive 

 granules, and which is now generally called the anther. [ANTHER.] 

 Ft is also extensively employed in cryptogamic botany. Among the 

 ferns, it is applied, in common with the terms capsule, conceptacle, 

 and sporangium [SPORAHQIUM], to those little granules which con- 

 stitute the manes called Sori. In the Kifuitctacece it expresses the 

 assemblage of cases which are attached to scales arranged in a conical 

 manner. 



The sime term is used to indicate tho kidney-shaped two-valvcd 

 ours that contain the reproductive matter of Lycopoaiacea, and also 

 the urn-like organs that inclose the sporules of mosses. It is by some 

 writers (till further extended, and used to express the parts that 

 contain the sporules in Lichens and funyi. 



THECADACTYLS. [QMXOBDJk] 



THKCI'l'KA. or THECI'DIUst [BRAcnioroDA.] 



THKCODOSTUSAU'RDS, a genus of extinct Saurian Reptiles 

 referred by Professor Owen to bis group of Thocodont Lacertians. 



Professor Owen, in his ' Report on British Fossil Reptiles,' observes 

 that among the inferior or eqoamate uurians there are two leading 

 modifications in the mode of attachment of the teeth, tho base of 

 which may be either ancbylosed to the summit of the alveolar ridge, 

 or to the bottom of an alveolar groove, and supported by its lateral 

 wall. These modifications are, be remarks, indicated respectively by 

 the terms 'acrodont' and ' pleurodont.' A third mode of fixation is 

 {inseuted by some extinct saurian*, which, in other parts of their 



organisation, adhere to the squamate or lacertine division of tlio order, 

 the teeth being implanted in socket*, either loosely or confluent with 

 the bony walls of the cavity : these Professor Owen has, in hin 

 ' Odontography,' termed the Thecodout Lacertians, the moat ancient of 

 all *aurians belonging to this group. 



The ThecodoHtotaurtu of Dr. Riley and Mr. Stulchbury, described 

 by them in the ' Geological Transactions ' of 1836, from remains 

 found in the dolomitic conglomerate of Redland, nc.ir Bristol, the 

 oldest or lowest division of the new red-sandstone series, is allied to 

 the typical Varanian Monitors, but differ* from them in having the 

 teeth imbedded in distinct sockets. The Varani, among the squamate 

 saurians, approach to this condition in the shallow cavities containing 

 the base of their teeth along the bottom of the alveolar groove. 



But, in the extinct genus now under consideration, the sockets are 

 deeper, and the inner alveolar wall is nearly as high as the outer one ; 

 the teeth are arranged in a close-set series, slightly decreasing in size 

 towards the posterior part of the jaw ; each branch of the lower jaw 

 is supposed to have contained 21 teeth, which ore conical, rather 

 slender, compressed and acutely pointed, with an anterior and posterior 

 finely-serrated edge, the serratures being directed towards the apex of 

 the tooth, as in G. Fischer's genus Rkopalodon ; the outer surface is 

 more convex than the inner one ; the apex is slightly recurved ; ami 

 the base of the crown contracts a little to form the subcylindrical 

 fang. The pulp-cavity remains open in the base of the crown ; and 

 in their microscopic structure the teeth of the Thccodontoiauriu closely 

 correspond with those of Varanut, Monitor, and Mryaloiauriu. 



The tooth of Paltroiaurta is compressed, pointed, and with trenchant 

 serrated margins ; but its breadth, compared with its length, is much 

 greater than in Thecodontotawnu. [PAI..EOSAURUS; TELEOSAURUS.] 



Professor Owen draws the following conclusions from the know- 

 ledge at present possessed of the osteology of Thecwlontomurtu and 

 Palanaaurtu, whose antiquity the discoverers of these genera regard 

 as being greater than that of any other vertebrated animals, excepting 

 fishes : 



In their thecodont type of dentition, biconcave vertebra), double 

 jointed ribs, and proportionate size of the bones or the extremities, 

 they are nearly allied to the Telauaurui ; but they combine a lacertian 

 form of tooth and structure of the pectoral and probably pelvic arch 

 with these crocodilian characters, having distinctive modifications, as 

 the moniliform spinal canal, in which however the almost contempo- 

 rary Kliynchosaur participates. 



THECODONTS. [THECODONTOSAUIIUS.] 



THECOSO'MATA (Gray), an order of Pteropodous Molliuca, it 

 includes the following families and genera : 



Family 1. Clcotlarida. 



Genera: Hyalaa; Diacria; Cleodora; Balantitun. ; Plcwoptu ; 

 Fayiiulla; Cratii; Brochtu ; Ptychc ; Euribia. 



Family 2. J.imacinidir. 



Qenus, Limacina. 



Family 8. Cuvierida. 



Genera: Cuvieria; Tripterei. 



Family 4. Cymliidiadcc. 



Genus, C'ymlnlia. 



THELI'DOMUS, (Swainson), a genus of Mullutra placed in tho 

 family Trochidtt, and in the sub-family Rotellintt. This so-called shell, 

 which is twice figured and described as that of a mollusc in the 

 ' Cabinet Cyclopaedia,' is the case of an insect. 



We notice the error, that a mistake in a useful book bearing thn 

 authority of a name so generally known and deservedly respected as 

 Mr. Swainson's, may not mislead. 



'Ill E'LODUS, a genus of Fossil Fish. [Fisii.] 



THELPHU'SA. [Tin 1 1 noin.v;.] 



THELPHU'SHMs, a tribe of Brachyurous Vnulacea belonging to 

 the family Catomctopa. The carapace bait but little or no convexity, 

 and is wider ftiau it is long: its anterior bonier is straight, and 

 occupies about two-thirds of its transversal diameter: its lateral 

 borders describe a regular curve. The front is remarkably wider than 

 tho buconl frame, and more or less curved downwards. The eyes 

 have a stout and short peduncle, the length of which in never more 

 than double the diameter, and its lower surface is occupied by the 

 cornea for about half its length. The orbits are oval, and always 

 present at their internal angle a narrow gap filled by the external 

 antenna. The internal antenna} are horizontal, and, in general, nearly 

 entirely hid by the front. The basilary joint of the external antenna 

 penetrates into the gap which occupies the internal angle of the orbit 

 and separates this cavity from the antennary foiwets ; it in but little 

 developed, and the moveable stem which springs from it in the same 

 gap is very small 



The habits of these animals are very remarkable. All the known 

 species live in the earth near the banks of rivers or in humid forests ; 

 bearing a strong analogy to the Land-Crab.*. (Milne-Edwards.) 



M. Milne-Edwards divides the tribe into three sections : 



1. Third joint of the external jaw-feet nearly square, and giving 

 insertion to the succeeding joint by a notch in its internal angle. 



Ex. T/itlfitiiua JlutiaMii. Length 2 4 inches. Colour yellowish. It U 

 found in the south of Italy, Greece, Egypt* and Syria. 



