COR 



[59 ] 



COR 



through, and permits objects to be re- 

 flected on the retina at the back. 



CO'RNEAN. A variety of clay-stone. 



CO'RNEOUS. (corneus, Lat.) Horny; of 

 a substance resembling horn ; of a horn- 

 colour. 



CORNE'HAN. For an account of this sub- 

 species of calcedony, see Carnelian. 



CO'RNBRASH. A coarse shelly limestone ; 

 a provincial term. Cornbrash is a ma- 

 rine deposit, a member of the oolite ; it 

 occurs in Wiltshire. 



CO'RNSTONE. A red limestone, occurring 

 in the old red sandstone. The name of 

 this and of the preceding word may be 

 considered as provincial, and given to 

 them from their presumed utility in pro- 

 ducing fertile corn-land. 



CORNU'TED. (cornutus, Lat.) Horned. 



CORO'LLA. (Lat.) The corolla consists of 

 the delicate petal, or petals, forming 

 what, in common language, are termed 

 the blossoms ; and in polypetalous flow- 

 ers, the petals are usually called the 

 leaves of the flower. The corolla consti- 

 tutes the beauty of the flower, and the 

 odour and fragancy of the plant fre- 

 quently reside therein, as in the rose, jes- 

 samine, violet, &c. The cerolla has a 

 diversity of forms, as well as of colour, 

 being found of every shade and variety 

 except black. It includes two parts, the 

 petals and the nectary : the latter is some- 

 times a part of the former, and some- 

 times separate from it. The leaves of the 

 corolla are called petals, and these are 

 either distinct, when the corolla is termed 

 polypetalous, as in the rose, ranunculus, 

 &c. or they are united by their edges, in 

 which case the corolla is said to be mono- 

 petalous, as in the honey-suckle, convol- 

 vulus, &c. The corolla is either regular 

 or irregular : when the petals are all alike 

 in size and form, the corolla having a 

 symmetrical appearance, it is called regu- 

 lar ; but when the petals are unequal, or 

 unlike each other, it is termed irregular, 

 as in the geranium, violet, &c. A papili- 

 onaceous corolla consists of five petals of 

 particular forms, of which the uppermost 

 is turned back, and is called the vexillum 

 or standard ; the two next resemble each 

 other, but differ from the first ; they 

 have their faces towards each other ; they 

 are called the alae, or wings; the remain- 

 ing two, which are placed below the 

 others, also resemble each other, but dif- 

 fer from the three already mentioned ; 

 they are usually united by their lower 

 edge, and form a figure resembling the 

 keel of a boat, whence they obtain the 

 name of carina, or keel. This corolla is 

 the characteristic of the leguminosse, a very 

 large order of plants, of which the broom, 

 lupin, sweet-pea, vetch, c. are examples. 



In some plants the corolla has one or 

 more of its petals spurred, as in the 

 violet. 



In the orchidese, the corolla consists of 

 three pieces, one differing very greatly in 

 form and size from the other two ; it is 

 called the labcllum, or little lip, and is 

 often spurred. In many species, this re- 

 sembles an insect. 



The lower part of the single petal of a 

 corolla, by which it is fixed to the recep- 

 tacle, is named the claw. 



The cruciferous plants have four petals, 

 and these are so arranged as to resemble 

 a cross, from which circumstance they 

 have been named Cruciferse. The stock, 

 radish, cabbage, mustard, &c. are exam- 

 ples. 



The outer part of the heads of many 

 composite flowers is formed of the ligu- 

 late corollas of the exterior florets, and 

 these are commonly white, blue, or yel- 

 low, as in the aster, daisy, &c. ; this part 

 of the head is termed the ray, the cen- 

 tral part being called the disk, which 

 disk is composed of florets, with regular 

 corollas. 



A corolla with two lips is called bilabi- 

 ate: when the two lips present an ap- 

 pearance resembling the mouth of an 

 animal, the corolla is called ringent. 



The petals of all corollas are placed 

 alternately with the sepals of the calyx. 



CORO'NA. (Lat.) In botany, an appen- 

 dage of the corolla or perianth. 



CO'RONOID. See Coracoid. 



CORO'NULA. A regular subrotund, or sub- 

 conical shell, divided into twelve arese, 

 with an opening both in the superior and 

 inferior part ; that in the superior closed 

 by a four-valved operculum. 



CO'RONATED. (coronatus, Lat.) In con- 

 chology, crowned, or girt towards the 

 apex with a single row of eminences. 



CO'RPUSCLE. \ (corpusculum, Lat. cor- 



CORPU'SCULE. $ puscule, Fr. corpuscolo, 

 It.) A minute particle of a body ; an 

 atom. 



CORRO'DED. (from corrodo, Lat. corrode, 

 Fr.) Eaten away by degrees ; consumed ; 

 worn away. 



CORRO'DENT. (from corrodo, Lat.) Hav- 

 ing the power of wasting, of wearing any- 

 thing away by degrees. 



CORRODIBI'LITY. The quality of being 

 corrosible. 



CORRO'DIBLE. } That may be worn away, 



CORRO'SIBLE. $ consumed, or corroded. 



CORRO'SION. (Fr. Faction ou Veffet de 

 ce qui est corrosif; corrosione, It.) A 

 dissolution of bodies by means of acids 

 or corrosive menstrua. 



CORRO'SIVE. (corrosif, Fr. corrosivo, It.) 

 Having the power of dissolving or gradu- 

 ally wearing away. 



