133 



OROBUS. 



ORTHOCERATID^E. 



134 



south of France. It has been rarely found in Great Britain in the 

 fields of Hampshire and Norfolk, and in Jersey. The flowers have a 

 bluish colour. 



0. ramosa has a calyx of 4 sepals, tubular, with triangular ovate 

 acuminate teeth, the anthers glabrous, the stem branched. This plant 

 is a native of Europe, and has been found in Great Britain in Norfolk 

 and Suffolk, where it grows on the roots of hemp and the Galeopsia 

 Tetrahit. 



The other British species are 0. amethystea, parasitical on Daucus 

 C'arota. 0. Picridig, found upon Picrit. 0. arenaira, on Achillaa 



(Babington, Manual of Brltiih Botany.) 



OROBUS, a genus of Plants belonging to the natural order Legit- 

 minotcc and the tribe Yiciece. It has a style linear, cylindrical, and 

 downy above ; the calyx is obtuse at the base, its upper segments 

 being deepest and shortest. 



0. tuberotta, the Tuberous Bitter Vetch, is a smooth plant with 

 winged stem ; leaves with 2-3 pair of elliptico-lanceolate inucronate 

 dotted leaflets; the peduncles few-flowered, hardly exceeding the 

 length of the leaves ; the teeth of the calyx unequal, ovate, bluntish, 

 shorter than the tube ; the legumes terete and obsoletely reticulated ; 

 the style joined and the seeds globose. This plant is a native through- 

 out Europe, and is abundant in Great Britain. It has creeping roots, 

 which swell out into tubers at irregular intervals. The tubers are 

 highly esteemed in the Highlands of Scotland, where they are called 

 Cormeille; the inhabitants dry them and chew them, in order to 

 give a better relish to their whiskey; and they are also supposed 

 to be good against diseases of the lungs, and to prevent hunger and 

 thirst in those who chew them. In Breadalbane and Ross-shire they 

 bruise and steep them, and distil an agreeable fermented liquor. The 

 tubers have a sweet taste, something like liquorice, and when boiled 

 are not unpleasant They have been used as food in times of scarcity. 

 In Holland and Belgium they are roasted and eaten in the same manner 

 as chestnuts. In England this plant is also known by the names of 

 Wood-Pea and Heath-Pea, and in Scotland Knapperte. 



O. luteui, Yellow Bitter Vetch, is a smooth plant with simple 

 angular stems, 3-5 pairs of leaflets, roundish semi-sagittate stipules, 

 elongated many-flowered peduncles, equal in length to the leaves ; the 

 legumes compressed, the seeds globose. This plant is a native of the 

 Alps of Switzerland, France, Italy, and Siberia. It has handsome 

 orange and yellow flowers, and Haller has expressed his opinion that 

 it is the handsomest of all the plants with papilionaceous flowers. 



0. niger, Black Bitter Vetch, has pinnate leaves with from 3-6 ovate 

 or elliptical leaflets ; linear-lanceolate acute stipules ; with an angular, 

 erect, and branched stem. It is a native of subalpine districts in 

 Europe. It is found in Forfarshire and Invernesa-shire in Scotland. 

 The flowers are purple, and the plant turns quite black on drying. 



There are about 40 other described species of Orobut. They are 

 all of them elegant-flowering plants, and being hardy, may be culti- 

 tivated on the open flower-border. 



ORONTIACE.E-, Orontiads, a natural order of Endogenous Plants, 

 under which Lindley, in his ' Vegetable Kingdom,' includes the A cannot 

 of Link and other authors. This order embraces the genera Calla, 

 Orontium, and Aconu, which are the types of three separate tribes. 

 They are related to Jtmcactoc, LUiacece, Piperacece, and Aracea. It 

 contains 13 genera and 70 species. Some of the species are used by 

 man. Symplocarjna fattidus, the Skunk Cabbage, yields a fetid volatile 

 oil. The rootstocks of Calla paluttrit are eatable. [AcoRiN.K.] 

 (Lindley, Vegetable Kingdom.) 



ORPHEUS. [MERC LID*.] 



ORPIMENT. [ARSENIC.] 



ORPINE. [SEDUM.] 



ORRIS-ROOT. [IRIS.] 



ORTALIDA. [CRACID*.] 



ORTHAGORISCUS, a genus of Plectognathous Fishes belonging 

 to the family Gymnodontidai. On account of their round form the 

 species are called Sun-Fishes. The genus has the following characters : 

 Jaws undivided, forming a cutting edge ; body compressed, deep 

 for its length, short, truncated, without spines ; tail short and very high 

 vertically ; rays of the dorsal and anal fins long and pointed, both 

 united at the caudal fin at the base. Two species of this curious 

 genus have been taken on the British coasts. 



0. mola, the Short Sun-Fish, the Molebut, although only occasionally 

 een, has been taken around all the shores of Great Britain. When 

 observed in our eas they have generally appeared as though they 

 were dead or dying, and floating along on one side, presenting the 

 broad surface of the other side to view. This seems to be a natural 

 position. 



". ohlongui, the Oblong Sun-Fiah, Oblong Tetrodon, Truncated Sun- 

 Fish. This fish is larger, longer, and rarer than the last. 



(Yarrell, Britith FMa.) 



ORTHITE, a Mineral consisting of Silicate of Cerium, Iron, &c. 

 This mineral occurs in minute, slender, columnar imbedded masses. 

 Fracture conchoidal. Hardness 6'0 to 7'0. Colour gray, inclining to 

 black. Streak brownish-gray. Lustre vitreous. Opaque. Specific 

 gravity 3-28H. Before the blow-pipe it swells and fuses into a blackish 

 globule ; with borax it gives a transparent glass ; gelatinises in acids, 

 and yields a solution of cerium. It is found at Finbo, near Fahlun in 



Sweden, and also in Greenland, &c. 

 from Finbo, by Berzelius, gives 



Silica 



Protoxide of Cerium 



Protoxide of Iron 



Alumina .... 



Lime 



Yttria .... 



Oxide of Manganese 



"Water 



The analysis of the mineral 



36-25 



17-39 



11-42 



14-00 



4-89 



3-80 



1-36 



8-70 



-97-81 



ORTHOCERAS. [ORTHOCERATID*.] 



ORTHOCERATID^E, a family of Cephalopodous Mollusca. It has 

 the following characters : Shell straight, curved, or discoidal ; body- 

 chamber small ; aperture contracted, sometimes extremely narrow ; 

 siphuncle complicated. This family is fossil. It includes the genera 

 Orthoceras, Qomphoctras, Onoceras, Phragmoceras, Cyrtoctras, Gyroceras, 

 and Ascoceras. 



The Orthoceratidce are connected on the one side with Nauttlidai, 

 and on the other with Ammonitidcc. These families are all many- 

 chambered, and have been called Cephalopoda polythalamacea. 



Three principal considerations have guided the geological naturalists, 

 to whom principally the divisions of the Nuutiloidal Cephalopoda are 

 due, in the arrangements which they have proposed : 



1. The spirality of the shell In Nautilus it is involute or convolute; 

 in Orthocera straight; and between perfect involution and absolute 

 straightuess we have every degree of curvature. 



2. The form in which the septa, whereby the cavity becomes con- 

 camerated, meet the inner surface of the shell. In most Nautili this 

 is a gentle and simple curve ; in many Orthocerata it is waved ; in 

 many Clymenia undulated, or deeply and angularly notched. 



3. The situation of the siphuncle on the disc of the septa. In most 

 Nautili the siphuncle is nearly in the centre of the disc ; in Clymenice 

 it is on or near the inner or ventral edge ; in Cyrtoceras generally near 

 to the outer or dorsal line. 



To these Mr. C. Stokes (' GeoL Proceedings ') has added, in the case 

 of the Othocerata, the consideration of the form of the siphuncle itself; 

 and Mr. Broderip (' Silurian Researches') has noticed, in the character 

 of Phragmocera, the form of the aperture and last chamber. 



It is difficult to be satisfied, while attempting the arrangement of 

 Nautiloidal Polythalamacea, with following out to its remote conse- 

 quences any one of these principles exclusively. From the general 

 figure we derive three main groups, namely : 



A. Orthocerata, Ac. Straight. 



B. Cyrtocerata, 4c. Incurved or convoluted near the apex, 



ending in a straight or recurved limb. 



C. Nautili, &c. Altogether convoluted. 



A. To subdivide these groups, we may take in Orthocerata, not the 

 septal edge, but the siphuncular structure; and, with Mr. Stokes, 

 separate Ormocerat, because of its tumid interruptal siphuncle ; and, 

 with Bronn, Actinocerai, because of its radiating siphuncular pro- 

 cesses. Species of Ormoceras belong to the Upper Palaeozoic Strata 

 generally, namely, to the Upper Silurian Rocks of Murchison, the 

 Devonian and Carboniferous Systems in Europe and North America, 

 above which they are unknown. Actinocerata have the same or a 

 more limited range. Orthoceratitei proper (excluding curved species, 

 like 0. paradoxicum, Sow.), have the same geological range, and exhibit 

 so great variation in the form of the cone, the disposition of the septa, 

 and situation of the siphuncle, as to furnish many helps to recognise 

 the otherwise undistinguishable forms of the 

 numerous species which fill the older rocks. 



For example, the cone is nearly a circular 

 base, the septa are transverse, and the si- 

 phuncle is nearly central, in 0. giganteum 

 and 0. cinctum of the Mountain Limestone ; 

 the cone has an elliptic base, oblique septa, 

 and an excentric siphuncle, in 0. lalerale, 

 0. Breynii of the Mountain Limestone, and 

 0. imbricatum of the Ludlow Kocks. 



The last chamber and the mouth also vary 

 in form. In one species from the Ludlow 

 Rocks the form of these parts has suggested 

 to Mr. Sowerby the generic name of Gompho- 

 cerai (' Silurian Researches ') ; and another, 

 from the Mountain Limestone, has received 

 the specific designation of 0. furiforme. 



It may be remarked that the cases are 

 few in which the apex of Orthocerata has 

 been actually observed : in several cases of 

 supposed straight shells the apicial part is 

 seen to be curved, and it is our conviction 

 that this is very much more common than 

 the heedless application of Orthoceras would 

 lead to suppose. 



The following are the characters of some of the genera : 



Orthocerai (Ap96s, straight, combined with ictpas, a horn), Breynius. 

 A straight concamerated shell, with septa regularly concave toward? 



Ortlioceraa laterale. 



