553 



RAVEN. 



RED-SANDSTONE FORMATION. 



551 



aiche, zechstein, and kupferschiefer, it makes a series of five terms 

 which may be classed and arranged in comparison with English 

 types and names. This is done by Von Meyer, after Sedgwick, 

 thus : 



German. English. 



Asche (friable marl), and Thin-bedded limestone of Knot- 



Stinkstein (thin-bedded fetid lime- tingley. 



stone). Coloured marls and gypsum. 



Rauchwacke (limestone). Yellow magnesian limestone. 



Zechstein (limestone). Compact limestone. 



Kupferschiefer (copper-slate). Marl-slate. 



We may perhaps prefer to view the asche, stinkstein, and rauch- 

 wacke, as altogether only one feeble upper group comparable with 

 the upper laminated and cellular limestones of Knottingley, and the 

 zechstein as equivalent to our yellow magnesian limestone, in which 

 case the Kupfersjhiefer is on the parallel of our marl-slate. These 

 formations contain the remains of the genus of fishes named 

 Pakeonucut. 



RAVEN, the common name of the Corvus Corax. We subjoin a 

 cut of the head and foot of this species omitted in the article CORVID.E, 

 where an account of this bird is given. 



Head and Foot of Raven. 



RAYED or RADIATE ANIMALS, RADIATA, a class of Inver- 

 tebrate Animals. It embraces the orders Echinodermata [EcHiNO- 

 DKRMATA], Acalepfue [ACALEPHiE], Entmoa. [ENTOZOA], Polypifera 

 [POLYMFERA], Porifera [SPO.NUIAD.E], and Infusoria [INFUSORIA.] It 

 has the following characters : The nervous system when present is 

 without ganglia, and is composed of single filaments, which are dis- 

 posed in a circular form around the buccal orifice. The organs of 

 the body are arranged in a radiate manner around the digestive 

 cavity. The organs of digestion consist of a single sac or short 

 alimentary canal. The animals are mostly aquatic, breathing by gills, 

 and usually free. Professor Owen in 1835 proposed a binary arrange- 

 ment of these animals, according as the nervous system was fila- 

 mentous or altogether absent. He observed that in those Radiata, of 

 Cuvier in which the nervous system could be most unequivocally 

 traced in a filamentary form, likewise presented an alimentary canal 

 suspended in a distinct abdominal cavity, and with a very few 

 exceptions, provided with a distinct outlet. The nerves were accom- 

 panied with a corresponding development of the muscular system. 

 The following is Professor Owen's plan : 



Sub-Kingdom RADIATA. 



Nematoneura. Acrila. 



Class Radiaria, Lamarck. 



i'chinoderma, CUT. Acalcplux, Cuv. 



Class Polypi, Cuv. 



Ciliobrachiata, Farre; Anthotoa, Khr. ; N udibracliiata, Farre. 

 Class Entozaa, Rudolph. 



Calelmintha, Owen. Stcretmintha, Owen. 



Class tnfutoria, Cuv. 



Roti/era, Ehr. 



Polyyaitria, Ehr. 



Some of the animals thus placed amongst the Radiata are removed 

 by other naturalists. Thus the C'diobrachiala of Farre are now fre- 

 quently referred to the Mollnsca [MOLLUSOA], and the Rotifera to the 

 Articulata. 



(Owen, Lectures on Comparative Anatomy.) 



RAZOR-BILL. [AUK.] 



RAZOR-FISH. [PTLOKIMA.] 



REALGAR. [ARSENIC.] 



REAUMURIACEvE, Reaumuriads, a natural order of Plants be- 

 longing to the Exogenous class. It has a 5-parted calyx, surrounded 

 externally by imbricated bracts ; 5 petals, hypogynous, unequal-sided, 

 sometimes having a pair of membranous plates planted upon their 

 middle; definite or indefinite, hypogynous, monadelphous, or poly- 

 adelphous stamens, with or without a hypogynous disc ; the anthers 

 ovate, turned inwards, an.d bursting longitudinally; 2-4-5 carpels, 

 partially separate from each other, surrounding a central placenta 

 which passes into the base of each ; 2 or 4 ascending anatropal ovules, 

 with filiform or subulate styles ; a capsular fruit with 2 to 5 valves 

 and as many cells, unless the number is diminished by abortion ; 

 shaggy definite erect seeds, with a straight embryo surrounded by a 

 small quantity of mealy albumen, and the radicle next the hilum. 

 The species of this order are small shrubs, with fleshy scale-like leaves, 

 which are alternate and have no stipules, and are overspread by 

 resinous sunk glands. 



This little order consists of three genera, Reaumuria, Hololachna, 

 and Eichwaldia, which were formerly referred to Tamaricaccce ; they 

 have however but little affinity with that order. Their true affinities 

 seem to be with tfypericacece, near to which Lindley has placed them. 

 The species are generally natives of the ccast of the Mediterranean, and 

 of salt plains in the milder parts of Northern Asia. 



The genus Reaumuria was named by Haselquist in honour of Rene 

 Antoine Ferchault de Reaumur. It has a 5-parted involucred calyx ; 

 5 petals, permanent, furnished at the base on each side with a ciliated 

 appendage ; numerous pentadelphous stamens ; 5-6 stigmas ; a 5-valved 

 5-celled capsule, with valves easily separating from the septa, and 

 shaggy seeds. 



R. vermiculata has subulate semi-terete imbricated leaves, crowded 

 on the branches. It is a native of Sicily, Bombay, and Egypt. This 

 plant resembles Salsola fruticoaa. It is used at Alexandria as a remedy 

 for the itch, being bruised and applied externally, and a decoction 

 taken internally. 



It. liyptricoidct has lanceolate flat rather remote leaves. It is a 

 native of Syria and Persia. These plants are elegant little shrubs of 

 easy culture, which thrive well in a mixture of sandy loam and peat; 

 and young cuttings will grow freely in sand under a hand-glaas. 



Hololachna (from S\os, ' entire,' and *4.x< r n, ' wool,' or ' thick hair ') 

 has a 4-5-parted calyx; 4-5-petals; 8-10 hypogynous monadelphous 

 stamens inserted into an hypogynous gland ; 24 short subulate styles ; 

 the capsule 2-4-angled, 2-4-valved, 2-4-celled; the seeds few, large, 

 surface shaggy. The only species is //. Songarica, found by Ehrenberg 

 in the Soongarian desert of Siberia. In cultivation this plant requires 

 to be watered with salt-water. All the plants of this order abound in 

 saline matter in their tissues. 



(Lindley, Vegetable Kingdom ; Don, Dichlamydeous Plants ; Lindley 

 Flora Medica.) 



RECEPTACLE, in Botany, is that part of the flower on which any 

 of the other organs rest. It represents the iuternodcs of the stem and 

 branches in their changed condition. It assumes a variety of forms, 

 and enters very variously into the forms of flowers and fruits. 

 [FLOWER ; CALATHIDIUM ; FRUIT.] 



RECEPTACULI'TES, a genus of Fossils proposed by Defrauce 

 synonymous with Ischaditei of Murchisou. 



RECURVIROSTRA. [AVOSKT.] 



RED-BREAST. [ERTTHACA.] 



RKD-DEER. [CERVID.E.] 



RED-EYE. [LEUCISCCB.] 



RED LEAD. [LEAD.] 



RED MARL. An argillaceous red portion of the series of rocks 

 between the Coal and Lias is thus termed in geology. Almost iden- 

 tical marls, similarly associated with red-sandstones, lie also in the 

 upper part of the coal, and below the coal and mountain limestone. 

 Nor would it be always easy to distinguish in specimens, or even in 

 sections on a large scale, the upper red marls immediately below the 

 lias of the Trent or the Avon from the red marls above the nou- 

 magnesian limestone of Kuottingley, those above the magnesian lime- 

 stone of Pontefract, those below the same limestone near Wetherby, 

 those in the upper part of the coal formation of Manchester, or below 

 the whole of the coal and mountain limestone in Monmouthshire. 



RED-SANDSTONE FORMATION. In geology the term Red- 

 Sandstone is used in a variety of senses, partly with reference to the 

 mere colour of certain rocks, and partly as expressing rocks of certain 

 geological periods. Thus we have in the latter sense New Red-Sand- 

 stone, Lower Red Sandstone, and Old Red-Sandstone; and on the conti- 

 nent, Alter Rother Sandstein, Neuer Rother Sandstein, le Vieux Ores 

 Rouge, le Nouveau Ores Rouge, &c. The Red-Sandstone also means, in 

 some geological works, either the upper part or the whole system of 

 the rocks, calcareous, argillaceous, and arenaceous, which occurs in 

 the series of strata between the coal formation and the lias. If we 



