PHY 



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P I S 



of natural bodies, and it includes natural 

 history and philosophy. 



PHYTI'VOROUS. (from 0wrov, Gr. a plant, 

 and voro, Lat. to devour.) Feeding on 

 plants. 



PHY'TOLITK. (from QVTOV, a plant, and 

 XiOoQ, a stone, Gr.) A petrified or fos- 

 silized plant. 



PHYTO'LOGIST. (from phytology.} One 

 skilled in the structure, &c. of plants. 



PHYTO'LOGY. (from tyvTov, a plant, and 

 X6yo, discourse, Gr.) That department 

 of science which treats of the nature, 

 habits, qualities, &c. of plants. 



PHYTO'PHAGOUS. (from 0wrov, a plant, 

 and Qaytlv, to eat, Gr.) Feeding on 

 plants ; devouring plants ; feeding upon 

 vegetable substances. 



PHYTOSAU'RUS. A fossil saurian disco- 

 vered in the saliferous formation. 



PHYTOZO'A. (from Qvrbv, a plant, and 

 Ztiov, an animal, Gr.) Plant-like animals. 

 Another, and more modern, as well as 

 appropriate, name for zoophytes. 



PIGME'NTUM NI'GRUM. A dark brown, or 

 nearly black substance, which covers the 

 surfaces of the choroid membrane of the 

 eye, and gives to it its colour. 



PI'LEUS. The name given to a genus of 

 fossil echini ; pileus is another name for 

 conulus. 



PI'LLAR. In conchology, the columella, or 

 perpendicular centre, which extends from 

 the base to the apex, in most of the 

 spiral shells. 



PI'LLAR-LIP. In conchology, a continua- 

 tion of the glossy process with which the 

 aperture of shells is lined, expanded on 

 the columella. 



PI'LOSE. (pilosus, Lat.) In entomology, 

 covered with dispersed, long, and bent 

 hairs. 



PI'MELITE. A variety of steatite, coloured 

 by chrome or nickel. 



PI'NEAL GLAND, (from pineus, Lat. a 

 pine.) The name given to a gland of the 

 brain from its supposed resemblance to a 

 pine. This gland was at one time sup- 

 posed to be the seat of the soul. 



PI'NNA. (pinna, Lat. the fin of a fish.) A 

 genus of marine bivalves belonging to 

 the family Mytalacea. A cuneiform, lon- 

 gitudinal bivalve, with an acute base, the 

 upper part gaping ; hinge without a 

 tooth, lateral, and very long ; valves 

 coalescent. Recent pinnse are found in 

 the ocean at depths varying to seventeen 

 fathoms ; they are moored by a long 

 silky byssus, which has been manufac- 

 tured into stockings and gloves. Pinnse 

 have been found fossil at Grignon, and in 

 the limestone of Gloucestershire, Wilt- 

 shire, and Somersetshire. 



PI'NNITE. A fossil pinna. 



PI'NNATE. (pinnatus, Lat. winged.) In 



botany, applied to compound leaves, com- 

 posed of many leaflets, placed on each 

 side of the petiole ; these are placed in 

 pairs opposite to each other, and, in some 

 cases, an odd leaflet at the termination, 

 or, in others, a tendril : of the former the 

 rose furnishes an example ; of the latter, 

 the vetch. 



PINNA'TIFID. In botany, applied to leaves 

 cut transversely into several deep, oblong, 

 parallel segments, the incisions reaching 

 nearly to the midrib, and dividing the 

 leaf into irregular forms, termed lobes. 

 The groundsel affords a familiar illus- 

 tration. 



PIPE-CLAY. The Pfeifenthon of Werner. 

 This is the purest kind of potter's clay, 

 and is called pipe-clay, from its being 

 manufactured into tobacco-pipes. It is 

 of a grey or greyish white colour ; is 

 infusible ; and on exposure to a strong 

 heat it becomes white. It is abundant 

 in Devonshire and Staffordshire. 



PISCI'VOROUS. (from piscis, a fish, and 

 voro, to devour, Lat.) Feeding on 

 fishes ; devouring fishes ; subsisting on 

 fishes. 



PI'SIFORM. (frompisum, a pea, and forma, 

 form, Lat.) Of the form of a pea ; hav- 

 ing a structure resembling peas. Gra- 

 nular iron ore is called pisiform iron ore, 

 from its containing small rounded masses 

 of the size of a pea. 



PI'SIFORM IRON ORE. )The pea ore of 



PI'SIFORM IRON STONE. $ Jameson ; pi- 

 siform iron stone of Kirwan. A variety 

 of argillaceous oxide of iron, occurring in 

 small masses or grains, nearly or quite 

 spherical, and often equal in size to a 

 pea, or even larger. These globules are 

 composed of thin, concentric layers, 

 which decrease in density as they ap- 

 proach the centre. The exterior layers 

 are compact, and present an even, glis- 

 tening fracture with a resinous lustre, 

 whereas the centre of the grain is almost 

 always friable, and has a dull earthy 

 fracture. They are easily broken, and 

 may be cut by a knife. Specific gravity 

 3'40. These grains, sometimes solitary, 

 are generally united by a ferruginous 

 cement, either calcareous or argillaceous, 

 which adheres to their surface. This 

 variety is composed of oxide of iron 71'5, 

 water 14-5, silex 7'5, alumine 3'5, oxide 

 of manganese 0'5. It is abundant in 

 France, Switzerland, and Germany ; oc- 

 curring in secondary rocks. It some- 

 times contains fossil shells, which become 

 penetrated with oxide of iron. Cleave- 

 land. 



PI'SOLITE. (from Triffov, a pea, and \lOoQ, 

 a stone.) So called from its resembling 

 an agglutination of pease. The pisolithe 

 of Brongniart ; the peastone of Jameson. 



