81 



OLEACE.E. 



OMPHALEA. 



by age becoming slightly rancid. Common olive-oil is of a deep 

 greenish or brownish-yellow colour, and an odour and taste more or 

 less subrancid. Its speci6c gravity is greater than the other. The 

 unripe fruit of the olive is preserved in brine, and eaten frequently a 

 dessert. 



The olive flourishes only in warm and comparatively dry parts ol 

 the world, as the south of France and Spain, in Italy, Sicily, Syria, 

 and the north of Africa. Humboldt has stated that "the olive 

 flourishes between 36 and 44 N. lat. ; wherever the mean annual 

 temperature is from 62'6 to 58'1, where the mean temperature ol 

 the coldest mouth is not below from 41 to 42'8, and that of the 

 whole summer from 71'6 to 73'4." Great cold is injurious to it, as 

 that of 1709 was to the olive-trees of France ; and as M. Bove states 

 that the olive thrives in Egypt, and Delile that it contributes to the 

 richps of the Fayoum, which is nearly in the latitude of Cairo, it is 

 evident that it is capable of bearing a greater degree of heat, as is 

 probable indeed from its being a native of Asia, having been cultivated 

 in early times in Syria and Palestine by the ancient Hebrews, and 

 known to them by the name of Zait, and to the Arabs by that ol 

 Xaitoon. It is said to have been introduced by the Phocajans into 

 Marseille. 



OLEACEjE, Olireicortt, a natural order of Monopetalous Exogenous 

 Plants, with a superior 2-celled ovary, a subvalvate corolla, two sta 

 metis, and a fruit with pendulous albuminous seeds. In the artificial 

 collocations of natural orders to be found in books, these plants are 

 usually stationed next Jatminacett, with which they have been even 

 combined. It is however probable that they have really as much 

 affinity with some cf the monopetalous dicarpous orders. Lindley, in 

 his ' Vegetable Kingdom,' arranges them in the Sulanal Alliance, and 

 gives their further affinitiis as with Aceracea, Jatminacece, and 

 Solanacca;. 



The species of the order best known in this country are, the Olive, 

 or Olca Europaa [OLEA] ; the Lilac, or Syringa rulyarit ; the Evergreen 

 Pliillyrea of many forms ; the Privet, or Liguttrum ; and the Fringe- 

 Tree, or Cldnnanlhut ; all corresponding in habit and in sensible 

 properties, which latter are very generally bitter and febrifugal. The 

 bark of the Olive has been extensively used by the French instead of 

 Cinchona, and the young fruits of the Common Lilac form an infusion 

 scarcely inferior to gentian. 



Olive (Olea Europaa). 



1, a Bower ; 2, an ovary divided vertically ; 3, a ripe fruit cut In half j 4, a 

 tone divided longitudinally. 



The most anomalous genus of the order is the Ash, which, in its 

 most genuine form, has no petals, and in the division called Omul has 

 the petals present, but separate to the base. It is however, in all essen- 

 tial circumstances, the tame in structure as the more regular genera; 

 and its relation to the order has been ingeniously proved by the fact 

 that the Olive and the Lilac will both live when grafted upon it. It 

 is from tin Orniu, or Flowering-Ash, that the bitter-sweet purgative 

 called manna i secreted. [FRAXINCS.] 



The order ha 24 genera and 130 species. 



OLEANDER. [NERIUM.] 



OLEOON SPAR, a Mineral consisting of Carbonate of Iron and 

 Manganese. Its primary form is an obtuse rhomboid. Cleavage on 

 the faces of the primary. Its colour is yellow, reddish-brown. Lustre 



1TAT. HIST. DIV. VOL. IV. 



vitreous. Hardness 4-0. Specific gravity 37<l 5. It is found at Ehren- 

 friedensdorf. Its analysis by Magnus gives 



Carbonate of Iron . . . . . 59'99 

 Carbonate of Manganese ..... 40'66 



- 100'65 



OLEIN. [ADIPOSE TISSUE ; FAT.] 

 OLIBANUM. [BOSWELLIA.] 

 OLIGISTE. [IRON.] 



OLIGOCLASE, a Mineral occurring crystallised. Its primary form 

 is an oblique rhombic prism. Colour white, yellowish, and greenish- 

 white. Fracture conchoidal, uneven. Hardness 6'0. Transparent, 

 sub-translucent. Specific gravity 2-64 to 2'67. It is found at Dan- 

 vikszoll near Stockholm, Arendal in Norway, &c. Its analysis by 

 Berzelius gives 



Silica 



Alumina 



Lime 



Magnesia .. 



Soda 



Potash 



Peroxide of Iron 



10016 

 OLI'GODON (Boi<S), a genus of Snakes. 



OLIVA. [VOLUT1D.E.] 



OLIVE-OIL. [OLEA.] 



OLIVE-TREE. [OLEA.] 



OLIVELLA, Mr. Swainson's name for a genus, or rather a sub-genus, 

 separated by him from Oliva ; and characterised as having two plaits 

 on the columella. 



OLIVENITE. [COPPER.] 



OLIVINE. [CHRYSOLITE.] 



OLYGY'RA. [HELIUMS.] 



OMALAXIS. [TROCHID.E.] 



OMALISUS. [LAMPYRID.E.] 



OMENTUM is a broad baud of membrane connecting two or more 

 of the abdominal viscera. The chief of these membranes is the great 

 omentum, or caul, which forms a large fold connecting the stomach 

 with the transverse arch of the colon ; others of less size and import- 

 ance connect the stomach and liver, and the stomach and spleen. 

 The great omentum always contains some fat surrounding its blood- 

 vessels, so that it looks like a network of fatty tissue, and it is one of 

 the chief seats of the accumulation of fat in corpulent persons, in 

 whom it contributes largely to the peculiar prominence of the 

 abdomen. 



OMMASTREPHES,a genus of Cuttle-Fishea belonging to the family 

 TeMhidor. Body fleshy, firm, cylindrical, elongated, flanked near its 

 posterior extremity by two triangular fins. Locomotive apparatus 

 formed of " conical perpendicular pits, each communicating by a 

 narrowed groove with a small horizontal pit, surrounded by a promi- 

 nent margin, the whole describing a rather prominent triangle, placed 

 at the base of the locomotive tube ; and, besides, of a tubercle pro- 

 longed into its upper part into a decreasing nose-shaped crest; and 

 lastly, of little horizontal inferior crests placed on the inner margin 

 of the body." Eyes very large, opening widely exteriorly, and 

 provided with a lachrymal sinus ; arms 10, like those of Loligo ; peu 

 corneous, flexible, elongated, as long as the body, terminating at its 

 lower extremity in a hollow simple cup. 



The Cuttlc-Fishes of this genus closely resemble those belonging to 

 Loligo. Besides the character just given, they may generally bo 

 distinguished by the short rhomboidal termination of the body, formed 

 by the fins, combined with the hinder extremity. 



The species are mostly pelagic, and some of them are gregarious. 

 They seem to be distributed all over the world. They are called 

 Flying Squids by fishermen. (Forbes and Hanley.) 



The following species have been taken on the British coasts : 



0. sti'jitfatvi (ilepia Loligo, Linnasus), with an elongated body ; 

 peduncles of tentacular arms without suckers; extremities of their 

 ilubs covered with closely-set rows of numerous minute suckers. 

 This species is very rare on the British coast, but Messrs. Forbes and 

 Hanley record, two instances of its recent capture. M. D'Orbigny 

 regards the Loligo Pitcatorum, L. llarjiayo, L. UUccbrosa, and L, 

 C'oindetii as founded on this species. 



0. todarui (Loligo sagittata, Lam.), Delle Chiajo. It has an elon- 

 gated body, and the peduncles of the tentacula provided with suckers 

 throughout their length. This squid is often called in British cata- 

 ogues Loligo tayittata. It is frequently found on the coasts of Great 

 Britain. It has been made the subject of an elaborate memoir on the 

 anatomy of its nervous system by Mr. Albany Hancock. 



0. Etilana, (Ball), has a short body ; suckers confined to the cluba 

 of the tentacles, minute, and 4-ranked at their extremities. It has 

 )een found in Dublin Bay, and was first described by Dr. It. Ball of 

 Dublin. 



(Forbes and Hanley, Hittory of British Mottutca). 

 OMPHALEA, a genus of Plants belonging to the natural order 

 iji/torljiacctc. The seeds of one of the species are said to be eatablo 

 when the embryo is extracted, but if this is not done, they are too 

 cathartic for food. On the authority of Mr. \V. M'Leay, Dr. Lindley 



