733 



MAYACACE^E. 



MEGALOPA. 



731 



M. judicalis of Bertoloni is the Mavi of the Kaffirs, and yields a 

 poisonous bark used by them as a test in judicial trials. 



MAYACACE-iE, Mayacs, a natural order of Endogenous moss-like 

 Plants, creeping over damp places, with narrow leaves, resembling 

 Spider- Worts, but differing in their 1-celled anthers, carpels opposite 

 the inner divisions of the perianth, 1-celled ovary and capsule, and 

 parietal placentas. The species, four in number, are natives of North 

 America. They are of no known use. (Balfour, Class-Book of Botany.) 



MAY-FLY, the popular name of the Neuropterous Insects of the 

 genus Ephemera and its allies. [EPHEMERA.] Baetis is one of the 

 genera of Ephemera. The Baetia venosa, an insect inhabiting a great 

 part of Europe, is the type, 



MAY-WEED. [ANTHEMIS.] 



MAZAMA. [ANTILOPE*.] 



MEADOW-SAFFRON. [CoLCHicuM.] 



MEALY-BUG. [CocciD.t.] 



MEANDRINA. [MADHEPHYLLICEA.] 



MEAT-FLY. [MuscA.] 



MECINUS. [CIQJJU3.] 



MECISTINA. [PARUS.] 



MECISTOPS. [CBOCODILID^.] 



MECONO'PSIS (from ufauv, a poppy, and Jtyis, a resemblance), a 

 genus of Plants belonging to the natural order Papaveracece, and for- 

 merly referred to Papaver. This genus stands between Papaver and 

 Arijeoifine. It has 4 petals, numerous stamens, a short style, 5-6-radiat- 

 ing free stigmas, the capsule obovate, opening by pores beneath the 

 apex. 



There is but one species, M. Camtrica, the Welsh Poppy, a native 

 of Great Britain, a rare plant. It is also found in many parts of 

 Europe. It has yellow flowers which are very fugacious, and are seated 

 on long peduncles which are indexed before the opening of the flower, 

 BO that the flower-bud is drooping. It is an ornamental plant, and 

 may be introduced into the garden. It will grow in a rich light soil, 

 in a shady situation. It may be propagated by dividing the roots, or 

 by seeds. 



M. Nepalemii, a Nepaul plant, is described as being extremely 

 poisonous, especially its roots. 



MEDICA'GO (from MrjSi/ri), the Greek name of one of the species), 

 a genus of Plants belonging to the natural order Leyuminosce, to the 

 tribe Loteas, and the sub-tribe Trifoliece. It has the calyx somewhat 

 cylindrical, 5-clrft, the [keel rather removed from the vexillum ; the 

 stamens diadelphous ; the legume many-seeded, of various forms, 

 reniform, falcate, or cochleate, but usually twisted in a spiral manner. 

 The species are herbs or shrubs, with the stipules usually cut ; the 

 leaves trifoliate, the leaflet usually toothed, and the peduncles 1-2-many 

 flowered. They are exceedingly numerous, upwards of 80 species 

 having been described. 



M. tatina, Lucern, has many-flowered racemes ; the pods compressed, 

 spiral, with two or three turns, downy, unarmed ; the pedicels shorter 

 than the calyx or bract ; the leaflets obovate, oblong, dentate above, 

 emarginate. This plant is a native of Europe, and is found wild 

 in England and Scotland. It has an erect stem, with yellow or 

 violet flowers. It a commonly cultivated in the fields of Europe, 

 and Babington says that " the wild specimens found are scarcely 

 naturalised." This is the MrjSoc^ of Theophrastus, ' Plant, de Caus.,' 

 lib. 2, cap. 20 ; and the Medico of Pliny, lib. 18, cap. 20. 



M. falcata has the racemes many-flowered, the pods compressed, 

 sickle-shaped, downy, unarmed ; the pedicels shorter than the calyx, 

 longer than the bract; the leaflets obovate-oblong, dentate above, 

 emarginate, mucronatc. It is a native of Europe on dry moun- 

 tainous pastures. In England it is a rare plant, but is occasionally 

 found on dry gravelly banks and old walls. This species is said to be 

 the Lucern which is cultivated in Switzerland. 



if. Lupulina, Black Medick, or Black Nonsuch, has many-flowered 

 dense oval spikes ; the pods compressed, kidney-shaped, with a spiral 

 point rugged with longitudinal branched prominent veins ; the stipules 

 obliquely ovate, slightly toothed ; the leaflets roundish-obovate, den- 

 ticulate above, emarginate, mucronate. It has a procumbent stem 

 with yellow flowers, and is a native of Europe in meadows, pastures, 

 and waste ground, and is plentiful in Great Britain. It affords 

 excellent fodder for sheep, and must be treated in the same way 

 as Luoern. 



M. arborea, Tree Medick, is a villous shrubby plant ; it has obovate- 

 cordate leaflets nearly entire ; the stipules linear, acute, entire ; the 

 peduncles racemose ; the legumes stipitate, twisted, reticulated from 

 transverse veins ; 2-3-seeded, the seeds somewhat kidney-shaped. 

 This plant is a native of the south of Europe, and appears to be the 

 Kimrro! of Theophrastus, 'Hist. Plant.,' lib. 4, cap. 5; lib. 1, cap. 9; 

 ' De Caus. Plant.,' lib. 5, cap. 6 ; and the KVTUITOS of Dioscorides, lib. 4, 

 cap. 113. It is also the Cytuut of the Romans : Pliny, lib. 13, cap. 24 ; 

 Virgil, ' Eel.,' L 79; ' Georg.,' ii. 431. 



Besides the first three species described above, M. tylvettrit, M. macu- 

 lala, M. minima, and M. denticulata aro natives of Great Britain. 

 M. mn-icattt was at one time admitted into the British Flora as 

 growing on the sea-shore at Orford in Suffolk ; Mr. Babington, in his 

 ' Manual,' states that he is " convinced, from personal observation, 

 that no such plant now exists in that locality." 



In cultivation the species may be easily raised from seed, and the 



shrubby species propagated by cuttings. The perennial herbaceous 

 species may be propagated by dividing their roots. 



(Babingtou, Manual Brit. Bot. ; Fraas, Synopsis Plantarum Flora; 

 Classics.) 



MEDICK. [MEDICAGO.] 



MEDJIDITE, , Mineral consisting of Sulphate of Uranium and 

 Lime. It is of a dark-amber colour, and found near Adriauople 

 in Turkey. 



MEDULLA OBLONGATA. [BRAIN.] 



MEDULLA SPINALIS. [Nanvous SYSTEM.] 



MEDULLIN, a name given to the Pith of the Sunflower, &c. 



MEDU'SA. [AcALEPH*;.] 



MEERSCHAUM, a Mineral belonging to the series of Silicates of 

 Magnesia. It is dull-white, opaque, and earthy, nearly like clay. Its 

 hardness is 2'0, and specific gravity 2'6 to 3'4. A variety from 

 Anatolia, analysed by Thomson, gave 



Silica 42-0 



30-5 



Water 



Lime 



Alumina 



23-0 

 2-3 

 2-0 



-99-8 



When heated it gives out water and a fetid smell, and becomes 

 hard and perfectly white. When first dug up it has a greasy feel, like 

 soap, and on this account is used by the Tartars in washing their 

 linen. It is known in Europe from its being made use of in Turkey 

 to make the bowls of tobacco-pipes, which are hence called meer- 

 schaums. These pipes are first imported into Germany, where they 

 are softened in tallow and wax, and then polished. 



Aphrodite and Quincite appear to be varieties. 



(Dana, Mineralogy.) 



MEGACEROS. [CERVID^.] 



MEGADERMA. [CHEIROPTERA.] 



MEGADESMA, a name given by Bowdich to a genus of Fresh- 

 Water Conchifera (Potamophila of Sowerby, Galathea, Lam.). 



MEGGER A. [CBOTALID.E.] 



MEGALI'CHTHYS, a genus of fossil Ganoid Fishes, from the 

 Carboniferous Strata of Edinburgh, Glasgow, Leeds, Manchester, 

 Wigan, &c. 



The Megalichthys is one of those genera which may rank amongst 

 the singular links connecting two great natural divisions, which are 

 apparently so strongly marked, and separated from one another so 

 widely, as to offer scarcely any points of resemblance. It combines 

 with many of the characters of a true fish many close and striking 

 analogies with reptiles ; and the teeth more especially so closely 

 resemble those of some crocodilean animals, that when first discovered 

 they were immediately referred to that class ; and not only the teeth 

 but the scales also seemed to Dr. Hibbert (by whom they were first 

 noticed) to indicate the same affinity. 



There exists however a family of Ganoid Fishes, containing many 

 extinct genera, represented in those existing by two genera, which 

 together include seven species, iu which the peculiar Sauroid character 

 of the teeth indicates this approach to the reptiles, which seems 

 carried to its height in the genus now under consideration. The 

 dimensions of the teeth of the Merjalichthys far exceed those of any 

 other fishes teeth that have yet been examined, one of them having 

 been found to measure nearly four inches in length, with a breadth at 

 the base of nearly two inches. They are however of two kinds, the 

 large teeth being accompanied by several very small ones, alternating 

 with them, and distributed over the whole of the inside of the mouth. 

 The teeth are conical, and possess a conical hollow at the base, in 

 which the next tooth is prepared, BO that there may be a constant 

 succession as in reptiles. 



The scales of the Megalichthys are of various forms, and exhibit a 

 coating of enamel of a nut-brown colour, and of the most brilliant 

 lustre. They are generally angular, and the surface is punctured like 

 that of the dermal scutes of the recent crocodile. Besides however 

 the angular scales, others have been found rounded, and of large size, 

 having externally a lamellar structure, and not exhibiting the shining 

 enamel so characteristic of the scales of Ganoid Fishes. The rounded 

 scales have been found as much as five inches in diameter. 



(Ansted, Principles of Geology; Agassiz, Recherches sur lea Poiasona 



MEGALOCHILUS. [DRACONINA.] 



MEGA'LODON, Goldfuss, a genus of Fossil Conchifera from the 

 Devonian Strata. 



MEGALONYX. [MEOATHERIID*.] 



MEGALO'PA (Leach), a genus of Macfurous Crustacea (Macropa of 

 Latreille). 



The external antennaj are setaceous, hardly one-fourth so long as 

 the carapace, and formed of elongated joints ; the intermediate ones 

 terminated by two bristle-like appendages, the upper of which is the 

 longest. External jaw-feet, with the two first joints compressed, the 

 second the shortest, and notched at the end for the insertion of the 

 others; anterior feet equal, iu form of didactylous pincers, rather 

 short and stout ; four last pair rather shorter, less stout, and termi- 

 nated by a single nail, which is a little curved ; carapace short, wide, 

 and a little depressed, terminated in front by a pointed rostrum, 



