SERPENTS. 



SESLERIA. 



738 



and masses of trap on passing through or being in contact with ume- 

 stone not unfrequently change the nature of that rock near the junc- 

 tion, and either fill it with serpentinous lines or masses, or produce 

 therein asbestic or steatitic admixtures. It is a very common circum- 

 stance among the primary limestones to find light-green veins and 

 strings of serpentine, and in the Pyrenees calcareous rocks compara- 

 tively of very recent date are similarly altered. 



As a mineral Serpentine occurs, although rarely, in right rectangular 

 prisms. It is usually massive and compact in texture, and of a dark- 

 green or blackish-green, colour. It also occurs in fibrous and lamellar 

 varieties. Its hardness is 2'5 to 4, and it may be cut with a knife. 

 Its specific gravity is 2-5 to 2'6. It becomes yellowish-gray on ex- 

 posure, and feels sometimes a little unctuous. The following varieties 

 are recognised : 



Precious Serpentine. Purer specimens of a rich oil-green colour, 

 and translucent, breaking with a splintery fracture. It ia a beautiful 

 stone when polished. It has the following composition : 



Silica 42-3 



Magnesia -II'- 



Protoxide of Iron 0'2 



Carbonic Acid 0'9 



Water 12'4 



100-0 



It gives off water when heated; becomes brownish-red before the 

 blow-pipe, but fuses only on the edges. 



Common Serpentine. Opaque, of dark-green shades of colour. 



PicT"lite, Schiller Asbestua. A Fibrous Serpentine, of an olive-green 

 colour, constituting seams in Serpentine. The fibres are coarse or fine, 

 and brittle. It resembles some forms of asbcstus, but differs in its 

 difficult fusibility. Thomson's Baltintorite belongs here. 



Marmolite. A foliated Serpentine, of greenish-white and light green 

 shades of colour, and pearly lustre, consisting of thin folia rather 

 easily separable. The folia are brittle, and the variety is thus dis- 

 tinguished from talc and brucite. It has the following composition : 



Silica 40-1 



Magnesia 41'4 



Protoxide of Iron 2'7 



Water .... ... 157 



99-9 



KerolHe. Near Marmolite, but folia not separable. 



Serpentine is a very handsome stone when polished. Beautiful 

 specimens from Cornwall, and other parts of England and Ireland, 

 may be seen in the Museum of Economic Geology, London. When 

 mixed with limestone it constitutes the Verd-Antique Marble. It 

 does not wear well, although at first it receives a fine polish. Chromic 

 iron is usually found disseminated through it. Dr. Jackson of 

 America has shown that Epsom salts or sulphate of magnesia may 

 be profitably manufactured from Serpentine. 



(Dana, Mineralogy.) 



SERPENTS. [OraiDiA.] 



SERPI'CULA (from ' serpo,' to creep, on account of the creeping 

 habits of the species), a small African and Indian genus of Plants 

 belonging to the natural order Ualoragacur.. The genus is characterised 

 by being moncecious. The male flowers have the calyx small, quadri- 

 partite. Petals 4. Stamens 4 to 8. Styles 4, sterile. The female 

 flowers have the calyx-tube adnate to the ovary, limb small, quadri- 

 partite. Petals and stamens wanting. Ovary 4-celled. Ovules and 

 styles 4. Nuts brittle, 1-celled, 1-seeded. The species form herba- 

 ceous creeping branched plants, with axillary flowers, the males being 

 pedicellate, and the female aggregated and almost sessile, though they 

 are but little known. The plants of this genus are not possessed of 

 any remarkable properties, but they must not be confounded with 

 the Herpicula now JfydrMa verticillata, of Roxburgh, which belongs 

 to the natural family of Hydrocharidacete, and which is used in India in 

 refining sugar, in the same way that clay is employed in other coun- 

 tries. A layer of the plant being spread upon the surface of the 

 sugar, water is allowed slowly to percolate through the mass. 



SERPULA. [ANNELIDA.] 



SERPULl'TES, a genus of Fossil Annelida. [ANNELIDA.] 



SERRAFALCUS, a genus of Plants belonging to the natural order 

 of Grasses and the tribe Festucinew. It has unequal herbaceous many- 

 flowered glumes, the lower are from 3- to 5-nerved, the upper 7 to 9. 

 The flower is oblong and trifid. The outer palea with a short seta 

 founded on three nerves from below the tip. The styles lateral, below 

 the summit of the fruit. The spikelets narrow at the top. 



8. tecalinut has a loose panicle slightly compound, the simple 

 peduncles about equalling the oblong glabrous spikelets, the flowers 

 at first loosely imbricated, afterwards distinct, about as long as the 

 straight awn, the outer palea not overlapping the next flower. The 

 flower is large and downy, the leaves hairy with nearly smooth sheaths. 

 It is a native of Great Britain. 



.S'. racemotut has a close or elongated erect panicle usually simple, 

 the *pikelets glabrous ovate and somewhat compressed. The midrib 

 of the glumes and palea scabrous towards the top, the leaves and 

 sheathes slightly hairy. It is a common species in sandy places in 

 the south of Great Britain. 



(Ouhington, Manual of Jiritinh Botany.) 



HEKKAXUS, a genus of Fishes belonging to the family Percidte. 



It has a single elongated dorsal fin, the rays of the anterior portion 

 spinous, the others flexible ; branchiostegous rays 7 ; small teeth in 

 both jaws on the palatine bones and the vomer, some elongated teeth 

 among the smaller ones ; cheeks and operculum covered with small 

 scales ; preoperculum serrated ; operculum ending in two or three 

 flattened points projecting backwards. 



Two species of this genus have been found on the British coasts, 

 which may be given as examples of the genus. 



& cabrilla, the Smooth Serranus, is the Perca cabrilla of Linnasus, 

 the Perca channus of Mr. Couch. It is abundant in the Mediterranean, 

 and not uncommon on the Cornish coast. 



& gigas, the Dusky Serranus, is the Perca roousta of Couch. It is 

 abundant in the Mediterranean, where it sometimes attains the weight 

 of 60 Ibs. It has been taken off the coast of Cornwall. 



(Yarrell, History of British Fishes.) 



SERRATULA, a genus of Compositous Plants of the order Cyna- 

 racea, and the section Serratulca;. The heads of flowers are dioocious 

 by abortion ; the involucre is imbricated, sharp, and unawned ; tho 

 scales of the receptacle split longitudinally into linear bristles ; fruit 

 compressed, not beaked, basal areola oblique ; the pappus persistent. 

 There is but one British species of this genus, 8. tinctoria, the Saw- 

 Wort. (Babington, Manual of British Botany.) 



SERRICORNES, the third family of Pentamerous CoUoptera. They 

 have four palpi ; elytra which cover the abdomen ; and antenna? which 

 are for the most part equal throughout, or smaller at the extremity. 

 The L'mnsean genera Buprestis, Elater, Lampyru, and Ptinus belong 

 to this family, as also do Melyris, Clerus, and Cebrio. .The Ptinus fur 

 is the little beetle whose larva; do so much damage among collections 

 of natural history. 



SERTULA'RIA, a Linntcan genus of Polypifera. 



SERTULA'RIAD^E, the name of a family of Polypifera, including 

 the genus Sertnlaria of Linnaeus. [HTDBOIDA.] 



SERTULARI/EA, De Blainville's name for the family of Polypiaria; 

 founded on the Linnacan genus Serlularia. 



SERUM, the name given to the fluid part of the blood, also to the 

 fluid poured upon the surface of serous membranes. [BLOOD ; 

 MEMBRANE.] 



SERVAL. [FELIDJS.] 



SERVICE-TREE. [PrRus.] 



SE'SAMUM (2Va/to><), a genus of Plants belonging to the natural 

 order Sesamacece, sometimes called Pedalinece, containing only few genera 

 and species. It is distinguished by having a 5-parted calyx ; corolla 

 with a short tube ; bell-shaped throat ; and the limb quiuquifld, 

 somewhat bilabiate. Stamens 4, didynamous, with the rudiments of 

 a fifth stamen ; stigma bilamellate ; capsule oblong, 4-celled, 2-valved ; 

 seeds numerous. 



The species, though now cultivated in many countries, are supposed 

 to have been originally natives of India. They form annual plants, 

 with opposite and alternate leaves, and axillary solitary flowers. The 

 species are by some considered to be five in number, that is, S. 

 orientate, S. Indicum, S. luteum, S. laciniatum, with 5. radiatum, said 

 to be a native of Guinea. Others consider them all to be varieties of 

 one species. These are cultivated in various countries, but especially 

 in India, Egypt, and Syria. They have also been taken to the West 

 Indies, where the plant is called Banglo and Oil-Plant. Scsamum 

 seeds are sometimes added to broths, frequently to cakes by the Jews, 

 and likewise in the East. 



SESARMA. [GRAPSID^] 



SESBA'NIA, a genus of Plants belonging to the natural order 

 JLefjumino8(E t which is so named from the Arabic name of the species, 

 which is indigenous in Egypt. The rest are found in the equinoctial 

 parts of the world, but the most remarkable in India. The genus is 

 characterised by having a 5-cleft or 5-toothed calyx ; the standard of 

 the corolla roundish, larger than the keel, which is obtuse, 2-edged at 

 the bas a , stamens diadelphous (9 and 1), with the sheath auricled at 

 the base ; legume elongated, slender, torulose, many-seeded. Tho 

 species form shrubs or herbs with abruptly pinnate leaves, many pairs 

 of leaflets, cauline stipules lanceolate, and the petiole ending in a 

 bristle point. Flowers axillary, racemose, usually yellow. 



ft. sEyyptiaca, the Egyptian species, found also in India, forms a 

 small and very elegant tree ; its wood is employed in making the best 

 charcoal for gunpowder. 



S. cannabina, the Dhanchi of Bengal, is not found wild. It is cul- 

 tivated on account of the fibres of its bark, which are coarse, but 

 more durable than some other substitutes for hemp, especially when 

 exposed to wet, and are therefore generally employed for the drag- 

 ropes and other cordage about fishing-nets. 



SESLE'RIA, a genus of Plants belonging to the natural order of 

 Grasses and the tribe Seslerieai. It has a spiked panicle, sessile spike- 1 

 lets tiled all round; the glumes are from 2- to C-flowered, nearly as 

 long as the spikelet ; the outer palece keeled and membranous, with a 

 scarious margin ending in 3 or 5 points ; the dorsal rib evanescent. 



S. cerwlea has an ovate slightly one-sided spike, the outer palea 

 terminating in 4 teeth, the dorsal rib rough, with a short excurreut 

 point, the leaves abrupt, with a minute rough point ; the roots are 

 tufted, the stem from 6 to 12 inches high; the spike about half an 

 inch long, and of a bluish-purple colour. This is the only British 

 species. It is found chiefly ou mountains. 



