PER 



[ 200 ] 



PET 



never before seen an animal of that kind. 

 The original has been deposited in the 

 Sydney Museum ; but having shown to 

 my friend Mr. Ogilvy a drawing of it, he 

 has noticed the discovery in the Pro- 

 ceedings of the Geological Society for 

 1838, describing the animal as belonging 

 to a new genus closely allied to Pera- 

 meles, but differing in the form of the 

 fore feet, which have only two middle 

 toes resembling those of a hog, and in 

 the total absence of tail. This genus re- 

 quires to be verified by an examination 

 of the specimens at Sydney. It may 

 eventually turn out to be a real Perameles, 

 and in that case be called Perameles 

 Ecaudatus, or, if generally distinct, Chae- 

 ropus Ecaudatus." 



PE'RCOLATE. (from per, through, and colo, 

 to strain, or filter. ) To filter through ; 

 to strain through ; to run through the 

 pores, as through a filter. 

 PERCOLA'TION. Filtration ; the act of run- 

 ning through the interstices of a stratum, 

 as the percolation of water. 

 PERE'NNIAL. (perennis, Lat. perenne, 

 It.) In botany, applied to plants that 

 live many years, bearing flowers and fruit 

 frequently. 



PERBO'LIATE. In botany, applied to leaves 

 when the stem appears to pass through 

 their substance. The common hare's-ear 

 is an example. 



PE'RIANTH. (from TrjpJ, about, and avBog, 

 a flower, Gr.) The calyx is so called 

 when it is united with the corolla, so as 

 to form only one floral envelope. 

 PERICA'RDIUM. (from Trtpi, round, and 

 Kapdia, the heart, Gr. pericarde, Fr. 

 pericardia, It.) The membrane which 

 envelopes the heart. 



PE'RICARP. (from Trtpi, round, and KapTroe, 

 fruit, Gr. pericarpe, Fr.) The ovarium, 

 when ripened into fruit, is called the 

 pericarp; this consists of three parts, 

 which in some fruits, as the peach and 

 plum, are easily separable. The outer 

 skin is called epicarp ; the fleshy part, 

 the sarcocarp ; the stone, or shell, the 

 endocarp. There are ten different kinds 

 of pericarps, namely, drupe, pome, berry, 

 follicle, silique, silicic, legume, capsule, 

 nut, and strobile. 



PERICLI'NIUM. The name given by foreign 

 botanists to a kind of involucre. See 

 Periphoranthium. 

 PE'RIDOT. The name given by Haiiy to 



prismatic chrysolite. 



PERIGE'E. (from Trepl, round, and yr), the 

 earth, Gr. perigee, Fr.) A term used 

 to denote that point where the sun is 

 nearest to the earth. The perigee of the 

 lunar orbit is the point where the moon 

 is nearest to the earth. 

 PERI'GYNOUS. (from irtpi t about, and 



yvvi}, a woman, Gr.) Inserted around 

 the pistil. When the stamens grow out 

 of the corolla, calyx, or perianth, or are 

 not in any way joined to the seed-vessel, 

 they are said to be perigynous. 

 PERIO'STETJM. (from Trtp/, around, and 

 dffTtbv, a bone, Gr. perioste, Fr.) The 

 membrane which covers all the bones ; 

 that, however, which covers the bones of 

 the skull is called the pericranium. 

 PERIPHORA'NTHIUM. When bracts are 

 collected into a whorl, as in umbelli- 

 ferous plants, they are said to form an 

 involucre, which, if very small, receives 

 the diminutive name of involucel. This 

 kind of organ is very remarkable in 

 compound - flowered plants, appearing 

 as if it constituted a calyx common to 

 many flowers ; and hence it used to be 

 called a common calyx. It, however, 

 does not differ from the involucre in any 

 thing more than its bracts being more 

 numerous, more closely packed, and pa- 

 rallel with each other, instead of diverging. 

 Foreign botanists have given the names 

 Periphoranthium and Periclinium to this 

 kind of involucre. 



PE'RNA. A genus established by Bru- 

 guieres. A flat, irregular, subequivalve, 

 compressed, foliaceous, marine, bivalve. 

 Several parallel cavities across the hinge 

 opposed to each other in the two valves, 

 and lodging as many elastic ligaments : 

 anterior margin with a passage for a 

 byssus. Recent Pernae are found at 

 depths varying to ten fathoms ; they are 

 littoral shells ; moored by their byssus 

 to mangrove trees and corals. Fossil 

 Pernse have been found on the borders of 

 the Rhine. 



PERSI'STENT. (from persisto, Lat. to 

 abide. ) In botany, opposed to deciduous. 

 Not withering and falling ; remaining. 

 PE'RSOXATE. A term applied to a mono- 

 petalous flower of an irregular form, the 

 border of the corolla having an oral ap- 

 pearance with the labia closed. 

 PE'RVIOUS. (pervius, Lat.) Admitting 



passage ; capable of being penetrated. 

 PK'TAL. (TrkraXov, Gr. petale, Fr.) The 

 name given to each leaf of the corolla, or 

 flower of a plant. 



PE'TALITE. A mineral, of a reddish, or 

 greyish-white colour, which has only been 

 found in Sweden. It consists of silica 77'0, 

 alumina 17*0, lithia 6*0 ; or according to 

 others, of silica 76-21, alumina 17'22, 

 lithia 5' 76. It occurs in a mine of black 

 iron-ore, associated with spodumene, fel- 

 spar, tourmaline, mica, and quartz. Its 

 fracture is foliated ; scratches glass ; 

 brittle, and translucent at the edges. 

 Specific gravity 2 -62. 



PE'TIOLE. (from petiolus, Lat. the stalk of 

 fruits.) In botany, a foot-stalk ; the 



