KO 



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ulated with the stem ; inflorescence 

 terminal or radical spikes, racemes 

 or panicles, occasionally solitary. 



Natives of all countries, except 

 very cold or very dry. There are 

 thirty-seven British, and, probably, 

 altogether not fewer than fifteen 

 hundred species. 



The flower of the orchidese is very 

 peculiar; the calyx and corolla 

 consist of three pieces each, and 

 one of those forming the latter, 

 differs very greatly in size and form 

 from the other two; it is called 

 the labellum, or little lip, and is 

 often spurred. In many species, 

 this resembles an insect, and hence 

 they have received the name of bee, 

 fly, spider, &c., &c. 



OECHI'DEOTJS. Belonging to the order 

 Orchideae ; parasitical plants. 



O'EDEE OP STJPEEPOSI'TION. That ar- 

 rangement of strata in which they 

 are invariably found. The order 

 of superposition is never inverted. 

 Strata are frequently absent, but 

 the order of superposition of such 

 as are present is invariably the 

 same. 



OEE. (erz, Germ.) A metallic com- 

 pound. Metals are found usually 

 combined with other substances : 

 the compounds they thus form are 

 called Ores, when the metal exists 

 in them in sufficient quantities to 

 form a considerable portion of the 



OEGA'NIC. (opyaviicos, Gr. organicus, 

 Lat. organique, Fr. orgdnico, It.) 

 Consisting of various^parts co-oper- 

 ating with each other; consisting 

 of natural instruments of action or 

 operation. 



OEGA'NIC BO'DIES. Such as possess 

 natural instruments of action; on 

 the action of each, and their co- 

 operation together, depend the 

 growth and perfection of the body. 



OBGA'NIC BEMAI'NS. The relics of what 

 were once living bodies : generally 

 applied to the fossil remains of 

 animals or plants. 



" Chemical analysis," says Mr 

 Parkinson, " has been called in to 

 the aid of the naturalist, in order 

 to account for the perfect state of 

 preservation observable in remains 

 organized with the most exquisite 

 delicacy, and which there is every 

 reason for supposing to have been 

 decomposable in their recent state. 

 From this investigation we learn 

 the manner in which these memo- 

 rials of the old world, so interesting 

 and so frail, have been preserved. 

 Some have been impregnated with 

 calcareous matter, others with sili- 

 cious, and others with iron and 

 copper pyrites." 



OEISK'ANY SANDSTONE. A member of 

 the North American Devonian 

 rocks, attaining a thickness of 200 

 feet, and by its fossils proved to be 

 contemporaneous with the Lower 

 Devonian group of the Rhine. 



OEISMO'LOGY. (from qpto/to?, defini- 

 tion, and Ao'ryos, discourse, Gr.) 

 Called also terminology. In ento- 

 mology, orismology contains the 

 various technical terms used in 

 explaining the perceptible differ- 

 ences in the body of an insect, and 

 at the same time acquaints us with 

 its exterior visible parts in the 

 several periods of its existence, 

 until its full and perfect develop- 

 ment. It is the very first requisite 

 of a precise orismology to apply an 

 exclusively proper term to each 

 constantly distinct and peculiar 

 part. 



OENITHI'CKNITES. (from opvis, a bird, 

 and 0/70), to touch, Gr.) The 

 footmarks of birds found in differ- 

 ent formations. Some recent dis- 

 coveries of ornithicknites are very 

 remarkable; the footsteps appear 

 in regular succession, on the con- 

 tinuous track of an animal in the 

 act of running or walking, with 

 the right and left foot always in 

 their relative places. An account 

 of these has been published by Prof. 

 Hitchcock, in the American Jour- 



