USED IN NATURAL HISTORY. 



107 



OIIVA'CEOUS. Being of a greenish 

 olive colour ; of the quality of 

 olives. 



OMA'SUM. Lat. The manyplies, or 

 third stomach of ruminants. 



OMNI'VOROUS. fr. lat. onmis, all ; vo- 

 rare, to eat. Applied to animals 

 that eat all kinds of food, both 

 animal and vegetable. 



OMPHALO'DIUM. fr. gr. omphalos, the 

 umbilicus. The centre of the hi- 

 lum of the seeds of plants, through 

 which the nutrient vessels pass 

 to the embryo. 



ON AGOA. fr. gr. onos, an ass ; agrios, 

 wild. The mountain horse, or a 

 wild ass. 



ONCHI'DIUM. A genus of gastero- 

 pods. (p. 41, Book v). 



Ojfis'cus. Lat. A wood-louse. 



ONOCRO'TALTJS. fr. gr. CMOS, an ass ; 

 krotos, noise. Systematic name of 

 the pelican. 



ONTO'LOGT. fr. gr. ontos, a being ; 

 logos, a description. A descrip- 

 tion of organized beings. 



O'OLITE. fr. gr. oon, an egg; lithos, 

 stone. A granular variety of car- 

 bonate of lime, frequently called 

 roestone. (p. 58, Book viii). 



O'OLITIC. Belonging or relating to 

 o'olite. 



O'OLOGY. fr. gr. oon, an egg ; logos, 

 a description. That department 

 of ornithology which treats of 

 eggs and nests. 



OOZO'A. fr. gr. oon, an egg; zoon, 

 an animal. Carus' name for one 

 of the primary divisions of the 

 animal kingdom. 



O'PAL. A brittle mineral, charac- 

 terized by its iridescent reflection 

 of light. It consists of silica with 

 about ten per cent, of water. 



O'PALKS'CEJTT. Resembling opal. 



OPALIZED WOOD. Wood which has 

 acquired a structure resembling 

 that of opal, being petrified by 

 siliceous earth. 



OPA'Q.UK. fr. lat. opacus, dark. In- 

 capable of transmitting light, 



OPEII'CULA. Lat. plur. of operculurn. 

 OPER'CULAR. Belonging to opercu- 



lum. Covered with a lid. 

 OPERCU'LIFORM. Having the figure 



arid position of a round lid of 



something. 

 OPER'CULUM. fr. lat. operire, to co- 



ver. The small door or cover 



which closes the entrance to a 



shell. A bony, moveable plate 



which, in a great many fishes, 

 .covers the gills or branchiae. 

 OPHI'DIA. fr. gr. ophis, serpent. Sys- 



tematic name of an order of rep- 



tiles. 

 OPHI'DIAN. Any reptile of the or- 



der of ophidia. 

 OPHI'DIOUS. Of the nature of, or 



belonging to serpents. 

 OPHIO'LOOT. fr. gr. ophis, a serpent j 



logos, description. That branch 



of herpetology which treats of 



serpents. 

 OPPOSITE. Standing against each 



other on opposite sides of the 



stem. 

 OPHTHA'LMIC. fr. gr. ophthalmos, the 



eye. Belonging to the eye. 

 OPSIG'OSTAL. fr. gr. opse, late ; geino- 



mai, to be produced. Produced 



at a late period. 

 OP'TIC. fr. gr. optomai, I see. Re- 



lating to vision. The principal 



nerve of vision is so called. 

 O'RAL. fr. lat. on'*, the mouth. Be- 



longing or relating to the mouth. 

 O'RAHGERY. A kind of gallery, for 



the preservation of orange-trees, 



during the winter. 

 ORBI'CULA. fr. lat. orots, a circle. 



A genus of brachiopod mollusks. 



(p. 90, Book v). 

 ORBI'CTJLAR. Spherical, circular, 



round. 

 ORBI' 



ORBI'CULAH. "> fr. lat. orbis, an orb. 

 ORBI'CULATE. 3 A plane surface, 



having a circular outline, (p. 42, 



Book vii). 



lat. orbis, a circle, The 



