Medu´sa. A genus of marine animals of the class Acalepha.

Megathe´rium. From the Gr. megas, great, and therion, beast. Name of a fossil quadruped.

Melaleu´ca. From the Gr. melas, black, and leukos, white. A genus of plants of the family of Myrtáceæ.

Mela´stoma. From the Gr. melas, black, and stoma, opening. A genus of plants of the family of Melastomáceæ.

Mel´ia. A genus of plants of the family of Meliáceæ.

Melofo´rmis. From the Lat. melo, a melon, and forma, shape. Melon-shaped.

Menopoma. From the Gr. menos, strong, and poma, cover. A genus of reptiles of the family of Salamanders. Specific name of a batrachian.

Menura. A genus of passerine birds. The Menura superba, the lyre-bird.

Mercury. Quicksilver. A metal which is liquid at the ordinary temperature.

Mese´meryan´themum. From the Gr. mesembria, the mid-day, and anthemum, flowering, because the flowers usually expand at that time. The fig marygold. A genus of plants of the family of Ficoides.

Me´sa. Span. A table.

Mespilus. From the Gr. mesos, half, and pilé, bullet, the fruit resembling a half ball. The medlar. A genus of plants of the family of Rosáceæ.

Met´alloid. Literally, resembling metal. The metals obtained from the alkalis and earths are called metalloids.

Metalli´ferous. Containing metal, or metals.

Metamor´phic. From the Gr. meta, indicating change, and morphe, form. Metamorphic rocks are those which are evidently of mechanical origin, but owing to the presumed action of heat, have undergone change. Altered rocks.

Metrosi´deros. From the Gr. metra, heart of a tree, and sideron, iron, in allusion to the hardness of its wood. A genus of plants of the family of Myrtáceæ.

Metur. A species of wild corn which grows in Iceland.

Mi´ca. From the Lat. mico, I shine. A mineral, generally found in thin elastic laminæ, soft, smooth, and of various colors and degrees of transparency. It is one of the constituents of granite.

Mica-schist. Germ. (Gr. schistos, slaty, easily split.) Mica-slate. A lamellar rock composed of quartz, ordinarily grayish, and a great quantity of brilliant lamellæ of mica arranged in scales, or extended leaves.

Mi´das. Name of a genus of monkeys; also, of a genus of reptiles.

Migrato´ria. Lat. Migrating.

Millingto´nia. Proper name. A genus of plants of the family of Bignoniáceæ.

Millepo´ra. From mil, a thousand, and pori, holes. A genus of stony polyps, or corallines.

Mimo´sa. From the Lat. mimus, a comedian, in allusion to its numerous varieties. A genus, and a tribe of plants.

Mi´ocene. From the Gr. meiôn, less, and kainos, recent. In geology a name of a group of rocks of the tertiary period.

Mi´nimum. Lat. The least.

Mira´ge. Fr. A kind of natural optical illusion, arising from the unequal refraction of the lower strata of the atmosphere. The illusive appearance of water in deserts is explained in this manner.

Misodendron. A genus of plants of the family of Lorantháceæ.

Mite´lla. A genus of plants of the family of Saxafragáceæ.

Mollusk. From the Lat. mollis, soft. Applied to certain soft animals which inhabit shells, as oysters.

Mollu´sca. A branch of the animal kingdom.

Mollu´scous. Belonging or relating to mollusks.

Molyb´denum. A white, brittle metal.

Monocotyle´don. From the Gr. monos, single, and kotuledon, seed-lobe. A single seed-lobe.

Monocotyle´donous. Relating to monocotyledon.

Mono´ceros. From the Gr. monos, single, and keras, horn. Having one horn.

Mo´nodon. From the Gr. monos, single, and odous, tooth. Name of a genus of aquatic mammals. The Narwhal.

Mone´ta. Lat. Belonging or relating to money.

Moni´liform. From the Lat. monile, a necklace. In form of a string of beads, necklace-like.

Mo´nitor. A genus of Saurian reptiles.

Monospe´rma. From the Gr. monos, single, sperma, seed. One-seeded. A specific name.

Mon´tia. A genus of plants of the family of Portuláceæ.

Mori´nda. A genus of plants of the family of Rubiáceæ.

Moraines. Longitudinal deposits of stony detritus found at the bases, and along the edges of all the great glaciers.

Mo´rus. Mulberry. A genus of plants of the family of Urti´ceæ.

Mosasau´rus. From Meuse, name of a river, and the Gr. sauros, a lizard. A genus of fossil reptiles.

Mos´chus. From the Gr, moschos, musk. A genus of mammals.

Moschi´ferus. Lat. Musk bearing; containing musk.

Mosses. Crytógamous parasites of the family of Lycopodeácæ.

Mu´cilage. A mixture of gum and water.

Mural. Belonging or relating to a wall.

Musa. The banana. A genus of plants of the family of Musáceæ.

Muschelkalk. German. Shell limestone.

Musci´pula. Lat. A fly trap or mouse trap.

Musicus. Lat. Relating to music; musical.

Mycetus. Name of a genus of monkeys.

Myopo´tamus. From the Gr. mus, a rat, and potamos, a river. A genus of gnawing mammals.

Myri´stica. A genus of plants of the family of Myrista´ceæ; Mystri´tica moschata, the nutmeg tree.

Myrtus. Myrtle. A genus of plants of the family of Myrta´ceæ.

Nana. From the Gr. nanos, a dwarf. A specific name.

Na´ptha. A limpid bitumen.

Narci´ssus. A genus of plants of the family of Amarylli´deæ.

Na´trium. A metal.

Natron. A subcarbonate of soda.

Nectary. That part of a flower which produces honey.

Nelum´bium. A genus of plants of the family of Nymphæ´ceæ. Sacred Bean.

Nestor. An extinct bird.

Neuro´ptera. From the Gr. neuron, a nerve, and pteron, wing. An order of insects.

New red sandstone. In geology, a system of rocks of the secondary formation.

Nickel. A white metal. It is the basis of “German Silver.”

Nigra. Lat. Black.

Nimbus. A rain cloud.

Ni´tida. Lat. Neat, clean, bright.

Nitrogen. A simple, permanently elastic fluid or gas, which constitutes four-fifths of the atmosphere, and is the basis of nitric acid.

Niva´lis. Lat. Snowy.

Non-conductor. Applied to substances which do not possess the property of transmitting electricity, or heat.

Notacanthus. From the Gr. nôtos, back, and akantha, a spine. A genus of fishes.

Nototherium. A fossil genus of marsupial mammals.

Notornis. An extinct bird.

Nummula´ria. From the Latin nummus, a coin. A family of Mollusks. Nummulites.

Nymphæ´a. A genus of plants of the family of Nymphæa´ceæ.

Nyssa. From the Gr. nussô, I prick. A genus of plants.

Obsi´dian. A glassy lava. Volcanic glass.

Ocean´ica. Lat. Relating to the ocean.

Oeno´thera. From the Gr. oinos, wine, and therô, I hunt. A genus of plants of the family of Oenothera´ceæ. Synonym of onagrariæ.

Odora´ta. Lat. Odorous.

Odoratissi´ma. Lat. Very, or most odorous.

Odori´fera. Lat. Odoriferous.

O´lea. Lat. Olive. A genus of plants of the family of Olea´ceæ.

Old red sandstone. A system of rocks of the secondary formation.

O´olite. From the Greek ôon, an egg, and lithos, stone. A granular variety of carbonate of lime, frequently called roestone.

O´pal. A brittle mineral, characterized by its iridescent reflection of light. It consists of silica with about ten per cent. of water.

O´pales´cent. Resembling opal.

Ophi´dian. From the Gr. ophis, a serpent; applied to reptiles of the order of Ophidia.

Ophice´phalus. From the Gr. ophis, serpent, and kephale, head. Serpent-head. A genus of acánthoptery´gian, or bony-finned fishes.

Or´chis. A genus of plants of the family of Orchid´eæ, named from most of the species being marked by two tubercles.

Orchid´eous. Relating to the genus orchis.

Organ. From the Gr. organon, an instrument. Part of an organized being, destined to exercise some particular function; for example, the ears are the organs of hearing, the muscles are the organs of motion.

Orga´nic. Relating to an organ. Organic remains, are the fossil remains of organized beings.

Organiza´tion. The mode or manner of structure of an organized being.

Organized. Composed of organs; having a mode of structure.

Ornithoryn´chus. From the Gr. ornis, ornithos, a bird, and rugchos, a beak. A genus of mammals, having the beak of a duck.

Or´tygis. From the Gr. ortux, a quail. A genus of birds.

Os´mium. From the Gr. osme, odour. A metal discovered in 1803, by Tennant.

Oscilla´tion. The act of moving backwards and forwards like a pendulum.

Ota´ria. From the Gr. ôtarion, a small ear. A genus of amphibious mammals, of the tribe of seals.

Out crop. In geology, the emergence of a rock in place, at the surface.

O´vary. In botany, that part of a flower in which the young seeds are contained.

Oxa´lis. A genus of plants of the family of Oxalideæ.

Oxle´ya. A genus of plants of the family of Cedrela´ceæ.

Oxygen. The vivifying gas which constitutes about one-fifth of the atmosphere, the presence of which is essential to life.

Ozo´ne. From the Gr. ozô, I smell of something. The odorous matter perceived when electricity passes from pointed bodies into the air.

Pachyder´mata. From the Gr. pachus, thick, and derma, skin. An order of mammals—Pachyderms.

Padi´na. Same as Zonária, a beautiful marine plant. Padina pavonia, or Zona´ria pavonia. Turkey feather.

Palap´teryx. From the Gr. palaios, ancient, and apteryx, formed from the Gr. a, privative, and pteron, wing, wingless. Name of a genus of fossil birds, discovered recently in New Zealand.

Palæothe´rium. From the Gr. palaios, ancient, and therion, beast. A fossil genus of pachyder´matous mammals.

Palæonto´logy. From the Gr. palaios, ancient, and on, a being or creature, and logos, discourse. That branch of zoological science which treats of fossil organic remains.

Palæ´ozoic. From the Gr. palaios, ancient, and zoe, life. Relating to ancient life; belonging or relating to fossils.

Palma rea´l. Spanish. Royal Palm.

Palla´dium. A white, hard, very maleable and ductile metal, which is susceptible of a fine polish. It is more difficult to melt than gold.

Palmel´la. A genus of plants of the family of Conferváceæ. Palmella nivalis, a plant of the snowy regions, which gives color to the snow amidst which it grows. Protococcus is the red snow plant.

Panda´nus. From the Malay name of the tree, pandang. Screw-pine. A genus of plants, of the family of Pandancæ. Pandanus candelabrum. Candlestick screw-pine.

Panda´na. Relating to, or resembling the Screw-pines.

Pa´nicum. Panic-grass. A genus of plants of the family of Gramineæ. Panicum miliaceum, millet, a grain used for feeding poultry in England.

Papa. Spanish. Pope. Specific name of a vulture.

Papy´rus. A genus of plants of the family of Cypera´ceæ. The Papyrus antiquorum yields the substance used as paper by the ancient Ægyptians.

Papyri´fera. From papyrus, a sort of paper, and fero, I bear. Paper-bearing.

Parhelia. Plural of parhelion.

Parhelion. From the Gr. para, for, elios, the sun, A mock sun. A meteor which consists in the simultaneous appearance of several suns, “fantastic images of the true one.”

Paradisa´ica. Lat. Belonging or relating to Paradise. A specific name.

Parna´ssus. A genus of lepidopterous insects of the tribe of Parna´ssidæ.

Passiflora. Abbreviation of flos, flower, and passionis, of the passion. Passion-flower, so called from a supposed resemblance between its floral organs, and the instruments of the Passion of our Saviour. An extensive and beautiful genus of plants.

Patago´nica. Lat. Relating to Patagonia. Specific name of a penguin.

Pavo´nia. Formed from the Latin, pavo, a peacock. A specific name.

Peat. The natural accumulation of vegetable matter on the surface of lands not in a state of cultivation; always moist to a greater or less degree, varying, according to the kind of plants to the decay of which the formation of peat is due.

Pelo´pium. A metal discovered by Prof. H. Rose.

Pelargo´nium. From the Gr. pelargos, a stork. Stork’s bill. A genus of plants of the family of Geraniáceæ.

Pela´sgic. After a mythological name of Jupiter.

Pen´dulum. From the Lat. pendo, I hang. A weight suspended at the end of a rod, so that it may vibrate from side to side in a plane, is called a pendulum.

Pennise´tum. From the Lat. penna, a feather or pen, and seta, a bristle. A genus of plants of the family of Grami´neæ.

Pep´lis. Gr. Water-purslane. A genus of plants of the family of Salicáriæ.

Per´mian. After the ancient kingdom of Permia. A name applied by Mr. Murchison to a system of rocks, consisting of an extensive group of fossiliferous strata, intermediate, in their geological position, between the Carboniferous and Triassic systems, the latter being the upper portion of the New Red Sandstone formation.

Perturbation. In astronomy, the deviation of a celestial body from the elliptic orbit which it would describe, if acted upon by no other attractive force than that of the sun, or central body about which it revolves.

Pe´tal. From the Gr. petalon, a leaf. A part of the corolla of a flower analogous to a leaf.

Petro´leum. From the Gr. petros, a rock, and the Lat. oleum, oil. Rock-oil, often called Barbadoes tar. A brown, liquid bitumen, found in the West Indies, Europe, &c.

Phala´nger. From the Gr. phalagx, a phalanx. A genus of marsupial or pouch-bearing mammals.

Phaneroga´mia. From the Gr. phaneros, evident, and gamos, marriage. Phanerógamous plants. Applied to plants having distinct flowers.

Phle´um. Cat’s tail grass. A genus of plants of the family of Grami´neæ.

Phlox. Gr. Flame. A genus of beautiful plants of the family of Polemoniáceæ.

Pho´cæ. Lat. Plural of phoca.

Pho´ca. Lat. A seal. A genus of aquatic mammals, embracing the common seal or Phoca vitulina; the Harp seal or P. oceanica; the Hare-tailed seal or P. lagura; the sea-lion; sea-wolf; sea-elephant; sea-cow; &c., &c.

Pho´nolite. From the Gr. phoneó, I resound, and lithos, a stone. Clinkstone. A kind of compact basalt which is sonorous when struck.

Phor´mium. From the Gr. phormos, a basket. Flax-lilly. A genus of plants of the family of Asphodéleæ. Phormium tenax, Iris-leaved flax-lilly of New Zealand.

Phos´phorus. From the Gr. phos, light, and pherô, I bear. A simple substance which is highly inflammable.

Phospho´ric acid. A compound of phosphorus and oxygen, having the properties of acids.

Phos´phates. Compounds of phosphoric acid with salifiable bases, as soda, are termed phosphates; Phosphate of soda, for example.

Phosphore´scence. Emission of light from substances at common temperatures, or below a red heat.

Phosphorescent. Having the property of emitting light without sensible heat.

Physa´lis. A genus of plants of the family of Solanáceæ. Physalis edulis, the Cape gooseberry.

Physe´ter. A blower. Name of a genus of mammals of the family of Ceta´cea.

Pime´nto. Allspice; Jamaica pepper.

Pinnate. From the Lat. pinnatus, feathered. Having leaflets arranged along each side of a common petiole, like the feather of a quill.

Pinnati´fida. Lat. Pinnatifid. A leaf is so called when it is divided into lobes from the margin nearly to the midrif.

Pinus. Lat. A pine-tree. A genus of plants of the family of Coniferæ. Pinus abies. The Norway Spruce. Pinus canariensis. The Canary pine. Pinus cembra. The Riga balsam tree; the Cembran or Siberian pine. Pinus excelsa. The lofty or Nepal pine. Pinus maritima. The maritime pine. Pinus pinea. The Stone pine.

Pipiens. Lat. Peeping like a chicken.

Pipa. A genus of batrachian reptiles. A kind of toad.

Pluto´nic rocks. Unstratified crystaline rocks, probably formed at great depths beneath the surface by igneous fusion. Volcanic rocks are formed near the surface.

Podoca´rpus. From the Gr. pous, podos, the foot, and karpos, fruit. A genus of plants of the family of Coniferæ.

Polarized light. Light so modified as to possess poles, or sides, having opposite properties.

Polariza´tion. Light, by reflexion, by passing through crystals possessing the power of double refraction, becomes modified, so that it does not present the same phenomena of transmission and reflection, as light which had not been polarized.

Polyg´onum. From the Gr. polus, many, and gonu, a knee or joint. A genus of plants of the family of Polygona´ceæ. Polygonum viriparum, Alpine Bistort.

Polymo´rpha. Lat. From the Gr. polus, many, and morphe, form. Many-shaped. A specific name.

Po´lypi. Lat. Plural of polypus.

Polyple´ctron. Name of a genus of birds.

Pol´ypus. From the Gr. polus, many, and pous, foot. A genus of radiate animals.

Pon´tica. From pontus, the sea. Belonging or relating to the sea.

Pontop´pida´na. Synonym of Couroupita. A genus of plants of the family of Myrtáceæ, Lecythideæ. A large tree of Guiana.

Ponto´phidan. From the Lat. pontus, the sea, and the Gr. ophis, a serpent. The sea serpent.

Portulaca´ria. A genus of plants of the family of Portula´ceæ. The Purslane-tree. Portulaca´ria afra. The African purslane-tree.

Porphyri´tic. Of the nature of porphyry.

Porphyry. From the Gr. porphura, purple. Originally applied to a red rock found in Egypt. A compact feldspathic rock containing disseminated crystals of feldspar, the latter when polished forming small angular spots, of a light color, thickly sprinkled over the surface. The rock is of various colors, dark green, red, blue, black, &c.

Portland bed. A name given by geologists to the superior division of the upper óolite or lias system. The “Portland stone” is a kind of limestone found in the south of England, and more particularly in the Isle of Portland. In this series of strata is a silicious sand known as the “Portland Sand.”

Potas´sium. A metal discovered in potash by Sir H. Davy in 1807.

Potenti´lla. A genus of plants of the family of Rosáceæ. Cinquefoil. Potentilla tridenta´ta. Trifid-leaved cinquefoil.

Pre´hensile. From the Lat. prehendere, to lay hold of. Having the faculty to lay hold of. Applied to the tails of those monkeys, for example, which have the power to suspend themselves by the tail.

Preda´ceous. Living on prey.

Primary formation. A term applied by geologists to designate the different rocks which were formed prior to the creation of plants and animals.

Primigenius. Lat. Original; first of its kind.

Pri´mum mo´bile. That which first imparts motion.

Prim´ula. Lat. A primrose. A genus of plants of the family of primuláceæ. Primula farino´sa, the Bird’s-eye primrose.

Prism. A solid bounded by three planes, two of which are equal.

Prismatic. Belonging or relating to a prism.

Probosci´dian. From the Gr. proboskis, a proboscis or trunk. Applied to mammals of the family which includes the elephant.

Procella´ria. From the Lat. procella, a tempest at sea. A genus of birds of the family of Palmipedes.

Proli´fera. Formed from proles, a race or stock, and fero, I bear. Prolific.

Pro´tea. A genus of plants of the family of Proteáceæ. Protea cyaneroides, Artichoke-flowered protea.

Pro´teus. A genus of reptiles.

Pteroca´rpus. From the Gr. pteron, a wing, and karpos, fruit. The pods have membranous wings. A genus of plants of the family of Leguminósæ. Pterocarpus santalinus. The red saunders tree.

Pte´ris. Gr. Name of Fern. A genus of cryptógamous plants. Brake. Pteris esculenta. Edible fern.

Pteropus. From the Gr. pteron, wing, and pous, foot. A genus of mammals of the tribe of bats, termed Roussettes.

Pu´ma. A name of the couguar or American Lion.

Pyroge´nous. From the Gr. pur, fire, and geinomai, I beget. Applied to rocks which owe their origin to the action of fire, as granite.

Py´rus. A genus of plants of the family Rosáceæ. A pear-tree.

Pyri´fera. Lat. From pyrus, a pear, and fero, I bear.

Python. A genus of reptiles.

Quadruma´na. Formed from the Lat. quatuor, four, and manus, hand. An order of mammals characterized by having four hands.

Qua´rtz. Germ. Rock crystal.

Quartzose. Of the nature of quartz.

Quicksilver. A metal which is fluid at ordinary temperatures. Also called mercury.

Radia´ta. Lat. Radiate; the name of a class of zóophytes.

Ra´diate. From the Lat. radius, a ray. Furnished with rays; having rays.

Radia´tion. The emission of the rays of light, or of heat, from a luminous or a heated body.

Raffle´sia. After Sir T. Raffles. A genus of plants of the family of Rafflesiáceæ, which are parasites, growing on the roots of dicotyledonous plants. The flowers of some of them are enormously large; the Rafflesia arnoldi are said to be three feet in diameter.

Raine´tte. Fr. A tree-frog.

Ranun´culus. From the Lat. rana, a frog, because the species inhabit humid places. Crow-foot. A genus of plants of the family of Ranunculáceæ.

Ranun´culi. Lat. Plural of ranunculus.

Ra´na. Lat. A frog. A genus of reptiles.

Refra´ction. From the Lat. refractus, broken. The deviation of a ray of light from its rectilinear course, caused by passing through a transparent substance. The degree of refraction depends upon the density of the medium through which the ray of light passes.

Refu´lgens. Lat. Shining brightly; refulgent.

Re´ptile. From the Lat. repere, to crawl. A term applied to any animal that moves naturally upon its belly, or on very short legs, as serpents, &c.

Repti´lia. The class of reptiles: it comprises those vertebrate animals which have cold blood, an aërial respiration, and an incomplete circulation.

Resenife´ra. Lat. Containing resin.

Revolu´ta. Lat. Turned back; tumbled.

Rhea. Synonyme of Struthio, an ostrich.

Rho´dium. From the Gr. rodon, a rose, on account of the rose red color of some of its salts. A metal discovered in the year 1803 by Wollaston.

Rhodode´ndron. From the Gr. rodon, a rose, and dendron, a tree. A genus of plants of the family of Ericáceæ.

Scie´ria. From the Gr. skleros, hard. A genus of plants of the family of Cyperáceæ.

Se´pia. A kind of paint prepared from the cuttle fish. A genus of mollusks.

Smyrne´nsis. Lat. Belonging, or relating to Smyrna.