PENTACT.E 



259 



PERIHELION 



five; krinon, lily.] Five-cornered lily, a 

 variety of stone lily. v. Encrinites/. 



Pentactae, (pen-tak'te). [Gk. pente, five; 

 actis, ray.] Sea-cucumbers: a sub-division 

 Of Echinodermata. 



Pentadesmis, ( pen-ta-des'mis ). [Gk. pente, 

 five; desmos, band.] A plant belonging to 

 Clusiacese. P. butyracea=T&llovf tree. 



Pentads, (pen 'tadz). [Gk. pente, five. j= Pen- 

 tatomic elements: equivalent to five atoms 

 of hydrogen; e.g., phosphorus, nitrogen, &c. 



Pentagon, (pen'ta-gon). [Gk. pente, five; 

 gonia, angle.] 1. Generally, 

 any plane figure formed by 

 five straight lines; specially, 

 a plane figure formed by five 

 equal sides. 



Pentamerus ( pen-tam'e-rua 

 [Gk. pente, five: rneros, part.] 

 1. A fossi. brachiopod, found Pentagon, 

 only in Palaeozoic rocks. 2. An insect belong- 

 ing to Coleoptera. 



Pentastoma, (pen-tas'to-ma). [Gk. pente, five-. 

 stoma. mouth.]-=Linguatula: a parasitic 

 animal, the type of Pentastoruidae, q.v 



Pentastomidae, (pent-ta-stom'i-de). [Penta- 

 stoma, q.v.] Animals belonging to Arach- 

 nida, parasitic on dogs, rabbits, <fcc.; with 

 long vermiform bodies; no respiratory or 

 circulating organs. 



Pentremites, (pen'tre-mits). [Gk. pente, five.] 

 A orinoid, known by fossil remains in coal 

 measures, v. Crinoidea. 



Pent-roof. [F. pente, slope.] A roof with 

 sloping sides. 



Pentunculus, (pen-tung'ku-lus). A marine 

 mollusc, known by fossil remains found in 

 Pliocene rocks. 



Pentyl, (pen'til). A new name for amyl. 



Penumbra, (pe-num'bra). [L. pene, almost; 

 umbra, shade.] The - B 

 lighter portion of a 

 shadow. 



Peony, (pe'o-ni). [M. 

 Paeon.] Paeonia : a 

 plant, with gay flowers, ' 

 belonging to Ranun- Penumbra, 



culaceae. S, sun; M, moon; 



Peplis, (pep'lis). [Pep- B A C, penumbra. 

 lion, the Greek name.] Water purslane: an 

 herb belonging to Lythracese. 



Pepper, (pep'per). [Piper, the Latin word.] 

 Bird P. =Capsicum frutescens. Black P.= 

 Drupesof Piper nigrum. Cayenne P.= Ground 

 seeds of capsicum, LonqP. =Spikesof Chavica 

 Roxburghii. Water P. = Polygon urn hydro- 

 piper. W/nte P.=Drupes of Piper nigrum, 

 with the black skin removed. P. moth 

 Biston. P. saxifrage Silaus. P. wort 

 Lepidium campestre. 



Pepperdulse=Laurentia pinnatifida: an edible 



Pepper- worts =:Piperacea?=Marsileaceje, q.v. 

 Pepsin, (pep'sin). [Gk. pepsis, cooking.] The 



peculiar protein compound which is the 



essential constituent of the gastric juice. 

 Peptic, (pep'tic). [Pepsin, q.v.] P. glands: 



in the lining of the stomach, which secrete 



the gastric juice. 



Peptones, (pep'tonz). [Pepsin, 9.v.]=Soluble 

 modifications of proteids; incipient albumin. 



Per-, a prefix implying the presence of a 

 chemical element in the highest proportion 

 known : as persulphide, peroxide. &c. 



Perameles, (per-a-me'lez). [Gk. pera, purse ; 

 meles, badger.]=Bandicoot=ThyJacis: a f ru- 

 givorousand insectivorous marsupial animal. 



Perca, (per'ka). [The Latin name.J=Perch: 

 a fresh-water fish, the type of Percidae, a 

 family of Acanthopterygii. 



Perch, (perch). [Perca, q.v.] v. Perca. Climb' 

 ing P. = An abas. 



Perchers=Insessores 



Perchlorates, ( per-klo'- 

 rats). [Perand Chlorates,* 

 q.v.] Compounds of per- 

 chloric acid with bases. Perch. 



Perchloric acid=HClO 4 =Hydric perchlorate: 

 a colourless volatile liquid, useful as an 

 oxidising agent, in contact with which 

 organic combustible substances catch fire. 



Perchlorinated ether=(C 2 Cl 5 ) 2 O=Ether in 

 which all the hydrogen has been displaced 

 by chlorine: a crystalline substance. 



Percnoptens, (perk-nop'ter-is). [Gk. perJcnos, 

 black ; pteron, wing.] A bird belonging to 

 Vulturidae, also called Pharaoh's chicken. 



Percussion cap. A small copper cap, contain- 

 ing mercuric fulminate, nitre, &c , which ia 

 exploded by percussion. 



Perdicidae, (per-dis'i-de). [Perdix, q.v.; Gk. 

 eidos,forn\.] Quails, &c.: a family of poultry- 

 like birds. 



Perdix, (per'diks). [The Latin name.] Part- 

 j ridge: a bird, the type of Perdicidae. 

 j Peregrine falcon, (per'e-grin). [L. peregrinus, 

 1 foreign.] Falco communis: a variety of the 

 falcon. 



Perennibranchiata, (per-en-ni-brang-ki-a'ta). 

 [L. perennis, perpetual; Gk. bragchia, gills.] 

 Amphibious animals which retain their gills 

 throughout life. 



Perianth, (pert-antli). [Gk. peri, about; 

 ant/ios, flower.] A general term for calyx 

 and corolla, or any modification of these. 



Pericardium, (per-i-kar'di-uro). [Gk. peri, 

 around; kardia, heart.] The membrane by 

 which the heart is surrounded. 



Pericarp,(per'i-karp). [Gk. peri, about; karpos, 

 fruit.] =Seed-vessel. q.v. 



Periclase, ( per'i-klaz ). 

 [Gk. peri, about, klasis, 

 fracture.] A mineral, 

 chiefly oxide of mag- 

 nesium. 



Peridot, (per'i-dot). [The <^' " --^ 



French name.] A green Pericarp, 



transparent variety of chr3 T solite. 



Perigee, (per'i-je). [Gk pen, about: ge, the 

 earth.] The point in the orbit of a planet, or 

 of the moon, which is nearest the earth. 



Perigymna, (per-i-jim'na). [Gk. peri, about; 

 gyrmios, naked.] Burmeister'a term for 

 Tunicata. 



Pengynous (pe-rij'i-nus). [Gk. peri, about; 

 gyne, woman.] Term used of plants having the 

 gtamens adhering to either calyx or corolla. 



Perihelion, (per-i-he'li-on). [Gk. pen, about; 



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