PLE 



PLO 



An order of fishes 

 comprising two families, the Gymnodon- 

 tes and the Sclerodermi, characterised by 

 having the maxillary bone soldered to 

 the side of the intermaxillary, which 

 alone constitutes the jaw, and the con- 

 nexion of the palatine arch to the cra- 

 nium by a suture. Hence also the name 

 from TtezTU, to bind, and ^vce.6os, a jaw. 



PLEC'TRTJM. The small ivory instru- 

 ment with which the ancients struck the 

 lyre. 



PLEDG'ET. In surgery, a compress or 

 small flat tent of lint, laid over a wound 

 to imbibe the matter discharged, and 

 keep it clean. 



PLEI'ADS, Lat. pleiades. A cluster of 

 seven stars in the neck of the constella- 

 tion Taurus : called by the Latins Ver~ 

 gilia, because they rose about the vernal 

 equinox. 



pterygious Ashes, of which the Plaice, 

 Flounder. Sole, Turbot. Halibut. &c., are 



species. Name from 



, the side, 



and HM, to swim, UT*JS, a swimmer, be- 

 cause they swim on the side. They have 

 also both eyes on the side, which is up- 

 permost when they are swimming, and 

 the upper side is always deeply coloured ; 

 whereas the other side is white. They 

 are taken along the coasts of almost all 

 countries, and furnish a delicious article 

 of food. They form, the family Platti. 

 Cuvier. 



PLEXIM'ETER, from jrXf|<j, percussion, 

 and /MTgov, measure. The name given 

 by M. Piorry to the ivory plate which he 

 uses in mediate percussion. 



PLEX'US. The Latin word for net-work : 

 applied to blood- vessels, nerves , &c . , when 

 many are near together, and the branches 

 cross and intertwine in the form of a net. 



PLEN'ARTT, Lat. plenus, full. In law, 

 the condition of an office, &c., when filled. PLI'CA, Plaited hair: from plico, to 

 JPLE'NUM (full). A term used in the j entangle. A disease of the hair, in which 

 it becomes long and coarse, and matted 

 and ghied into inextricable tangles. It 

 is peculiar to Poland, Lithuania, and 

 Tartary : hence called Plica Polonica. 



PLI'OATS. Lat. plicatus, plaited, folded. 

 Applied to leaves when the disc is acutely 

 folded up and down. 

 PLICITEN'NES, from plico, to fold, and 



Cartesian philosophy to denote the com 

 plete occupation of space by matter : op- 

 posed to vacuum. 



PLE'ONASM, Lat. pleonasmus, Gr. *>Ua- 

 OLtrfJko?, from jrXser, full. In rhetoric, a 

 form of expression in which more words 

 are used than are necessary: a redun- 

 dancy of words used to express a thought, 



r. of tie 

 . eom- 



as " I saw it myself with my oion eyes." 

 where the words in italics are 



PLEROSAU'RUS. A fossil 

 lias and oolite. Name from 

 plete, and iraiuqai. a lizard. 



PLESIOMOR'PHISM, xKufiot, near, and 

 /4f*5> form. The state of crystallised 

 substances, of which the forms are neaaly 

 identical. 



PLERIOSAT;'' 



marine saurians, of which prodigious 



pcnna, a wing. A fami'y of neuropterous 

 insects, in which the inferior wings are 

 usuarly wider tnan the others, and plaited 

 longitudinally. 



PLINTH, from arA/vflo?, a brick or tile. 

 1. A term is architecture, for a flat square 

 memfer in form of a brick, which serves 

 as the foundation of a column, being the 

 flat square table under the moulding of 

 the base and pedestal, at the bottom of 

 An extinct genus ofvj the order. 2. The plinth of a wall, is 



two or three rows of bricks, which pro- 



numbers are found in the lias- NaaJie j j ec t from it in form of a platband ; and 

 from nXytrtov, near, and ravine., a lizari. i^ general, any flat high moulding which 



Some individuals have been found up- 

 wards of 20 feet long. 



PLETJ'RA. nXtt/. The Greek word 

 for a rib, or the side of the thorax formed 

 by the ribs ; but now applied by anato- 

 mists to the membrane which lines the 

 internal surface of the thorax, and covers 

 its viscera. It forms a great process, the 

 mediastinum, which divides the thorax 

 into two cavities. 



PLEUROBRAN'CHUS. A genus of gaste- 

 ropods established by Cuvier : order 

 Tectibranchiata. Name from ;rAu>a, the 

 side, and fyayx,ict, branchia. The bran- 

 chiae being attached along the right side, 

 in the farrow between the mantle and 

 the foot. Various large and beautiful 



serves, in a front wall, to make the floors, 

 sustain the eaves of a wall, or the lamier 

 of a chimney. 



PLI'OCENE, from irXeloov, more, and 

 KO.IVOS, recent The name given by Sir C. 

 Lyell to two of his four divisions of the 

 tertiary strata ; the eocene, miocene, older 

 pliocene, and newer pliocene or pliestocene, 

 as then characterised by the proportions of 

 recent fossils they were supposed to contain ; 

 the newer pliocene then showir.e from 90 to 

 95 per cent. ; the older pliocene from 30 to 

 35 per cent. ; the mlocn 18, and the eocene 

 34 per cent. 



PLOT, 1 In surveying, a plan or horizon- 

 PI,AT, J tal section of an/ piece of land, 

 country, or works. 



