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An illustration of the first stage of fission in the Noctiluca scintillans. Noctiluca scintillans, also published as Noctiluca miliaris, is a free-living non-parasitic marine-dwelling species of dinoflagellate that exhibits bioluminescence. The bioluminescent characteristic of N. scintillans is produced by a luciferin-luciferase system located in thousands of spherically shaped organelles, or "microsources", located throughout the cytoplasm of this single-celled protist. Nonluminescent populations within the genus Noctiluca lack these microsources.

Stage One in the Fission of Noctiluca Scintillans

An illustration of the first stage of fission in the Noctiluca scintillans. Noctiluca scintillans, also…

An illustration of the second stage of fission in the Noctiluca scintillans. Noctiluca scintillans, also published as Noctiluca miliaris, is a free-living non-parasitic marine-dwelling species of dinoflagellate that exhibits bioluminescence. The bioluminescent characteristic of N. scintillans is produced by a luciferin-luciferase system located in thousands of spherically shaped organelles, or "microsources", located throughout the cytoplasm of this single-celled protist. Nonluminescent populations within the genus Noctiluca lack these microsources.

Stage Two in the Fission of Noctiluca Scintillans

An illustration of the second stage of fission in the Noctiluca scintillans. Noctiluca scintillans,…

An illustration of the aboral side view of the Noctiluca scintillans. Noctiluca scintillans, also published as Noctiluca miliaris, is a free-living non-parasitic marine-dwelling species of dinoflagellate that exhibits bioluminescence. The bioluminescent characteristic of N. scintillans is produced by a luciferin-luciferase system located in thousands of spherically shaped organelles, or "microsources", located throughout the cytoplasm of this single-celled protist. Nonluminescent populations within the genus Noctiluca lack these microsources.

Aboral Side View of the Noctiluca Scintillans

An illustration of the aboral side view of the Noctiluca scintillans. Noctiluca scintillans, also published…

An illustration of the Noctiluca scintillans. Noctiluca scintillans, also published as Noctiluca miliaris, is a free-living non-parasitic marine-dwelling species of dinoflagellate that exhibits bioluminescence. The bioluminescent characteristic of N. scintillans is produced by a luciferin-luciferase system located in thousands of spherically shaped organelles, or "microsources", located throughout the cytoplasm of this single-celled protist. Nonluminescent populations within the genus Noctiluca lack these microsources.

Noctiluca Scintillans

An illustration of the Noctiluca scintillans. Noctiluca scintillans, also published as Noctiluca miliaris,…

An illustration of the lateral view of the Noctiluca scintillans. Noctiluca scintillans, also published as Noctiluca miliaris, is a free-living non-parasitic marine-dwelling species of dinoflagellate that exhibits bioluminescence. The bioluminescent characteristic of N. scintillans is produced by a luciferin-luciferase system located in thousands of spherically shaped organelles, or "microsources", located throughout the cytoplasm of this single-celled protist. Nonluminescent populations within the genus Noctiluca lack these microsources.

Lateral View of Noctiluca Scintillans

An illustration of the lateral view of the Noctiluca scintillans. Noctiluca scintillans, also published…

Oxalis is the largest genus in the wood sorrel family Oxalidaceae. Of the approximately 900 known species in the Oxalidaceae, 800 belong to Oxalis. Many of the species are known as Wood Sorrel or Woodsorrel. The genus occurs throughout most of the world, except for the polar areas; species diversity is particularly rich in tropical Brazil and Mexico and in South Africa.

Oxalis

Oxalis is the largest genus in the wood sorrel family Oxalidaceae. Of the approximately 900 known species…

"Human Thoracic Duct and Azygous Veins. a, receptacle of the chyle; b, trunk of the thoracic duct, opening at c into root of left innominate vein at junction of f, left jugular, and g, left subclavian vein; e, right innominate vein; d, d, d, several thoracic and lumbar lymphatic glands; h, h, a short portion of the esophagus. Two azygous veins run parallel with and on each side of the duct, until the left crosses behind the duct to join the right. The structures represented rest nearly upon the back-bone." -Whitney, 1911

Thoracic Duct

"Human Thoracic Duct and Azygous Veins. a, receptacle of the chyle; b, trunk of the thoracic duct, opening…

The obverse side of the dupondius, "a Roman bronze coin, of the value of 2 asses." -Whitney, 1911

Dupondius, Obverse

The obverse side of the dupondius, "a Roman bronze coin, of the value of 2 asses." -Whitney, 1911

The reverse side of the dupondius, "a Roman bronze coin, of the value of 2 asses." -Whitney, 1911

Dupondius, Revers

The reverse side of the dupondius, "a Roman bronze coin, of the value of 2 asses." -Whitney, 1911

An illustration of the pistil, female reproductive part of the flower, from the mouse-ear chickweed. Cerastium is a genus of annual, winter annual, or perennial plants belonging to the family Caryophyllaceae. The around 100 species are commonly called Mouse-ear chickweed; different species are found nearly worldwide but the greatest concentration is mainly from the northern temperate areas of the world. A number are common weeds in fields and on disturbed ground.

Mouse-ear Chickweed

An illustration of the pistil, female reproductive part of the flower, from the mouse-ear chickweed.…

The cassava, yuca, manioc, mogo or mandioca (Manihot esculenta) is a woody shrub of the Euphorbiaceae (spurge family) native to South America that is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates. Cassava is the third largest source of carbohydrates for human food in the world, with Africa its largest center of production. The flour made of the roots is called tapioca.

Yuca

The cassava, yuca, manioc, mogo or mandioca (Manihot esculenta) is a woody shrub of the Euphorbiaceae…

Beaumaris Castle, located in Beaumaris, Anglesey, Wales was built as part of King Edward I's campaign to conquer the north of Wales. It was designed by James of St. George and was begun in 1295, but never completed. Beaumaris has been designated as a World Heritage site, and is regarded by some to be the most architecturally perfect castle in Britain.

Beaumaris Castle

Beaumaris Castle, located in Beaumaris, Anglesey, Wales was built as part of King Edward I's campaign…

The wels catfish is a scaleless fresh and brackish water catfish recognizable by its broad, flat head and wide mouth. The mouth contains lines of numerous small teeth, two long barbels on the upper jaw and four shorter barbels on the lower jaw. It has a long anal fin that extends to the caudal fin, and a small sharp dorsal fin positioned relatively far forward. It uses its sharp pectoral fins to capture prey. With these fins, it creates an eddy to disorient its victim, which it then simply engulfs in its enormous throat. It has very slippery green-brown skin. Its belly is pale yellow or white. Wels catfish can live for at least thirty years and have very good hearing.

Wels Catfish

The wels catfish is a scaleless fresh and brackish water catfish recognizable by its broad, flat head…

An illustration of the floor plan of Canterbury Cathedral. Canterbury Cathedral in Canterbury, Kent, is one of the oldest and most famous Christian structures in England and forms part of a World Heritage Site. It is the cathedral of the Archbishop of Canterbury, leader of the Church of England and the worldwide Anglican Communion. Its formal title is the Cathedral and Metropolitical Church of Christ at Canterbury.

Canterbury Cathedral

An illustration of the floor plan of Canterbury Cathedral. Canterbury Cathedral in Canterbury, Kent,…

An illustration of the floor plan of Durham Cathedral. The Cathedral Church of Christ, Blessed Mary the Virgin and St Cuthbert of Durham, commonly referred to as Durham Cathedral, in the city of Durham, England, was founded in AD 1093 and remains a centre for Christian worship today. It is generally regarded as one of the finest examples of a Norman cathedral and has been designated a UNESCO World Heritage Site along with nearby Durham Castle, which faces it across Palace Green, high above the River Wear.

Durham Cathedral

An illustration of the floor plan of Durham Cathedral. The Cathedral Church of Christ, Blessed Mary…

An illustration of a female nautilus without the shell. "m, The dorsal "hood" formed by the enlargement of the outer or annular lobe of the forefoot, and corresponding to the sheaths of two tentacles; n. Tentacular sheaths of lateral portion of the annular lobe; u, The left eye; b, The nuchal plate, continuous at its right and left posterior angles with the root of the mid-foot, and corresponding to the nuchal cartilage of Sepia; c, Visceral hump; d, The free margin of the mantle-skirt,...; g.a, Points to the lateral continuation of the nuchal plate b to join the root of the mid foot of siphon." (Britannica, 1910).

Female Nautilus without Shell

An illustration of a female nautilus without the shell. "m, The dorsal "hood" formed by the enlargement…

An illustration of the postero-ventral view female nautilus without the shell. "a, Muscular band passing from the mid-foot to the integument; b, The valve on the surface of the funnel, partially concealed by the inrolled lateral margin of the latter; c, The mantle-skirt retroverted; an, The median anus; x, Post-anal papilla of unknown significance; g.n., Nidamental gland ; r.ov, Aperture oft he right oviduct; l.ov, Aperture of the rudimentary left oviduct; neph.a, Aperture of the left anterior renal sac; neph.p, Aperture of the left posterior renal sac; viscper, Left aperture of the viscero-pericardial sac; olf, The left osphradium placed near the base of the anterior gill-plume." (Britnnica, 1910)

Female Nautilus without Shell

An illustration of the postero-ventral view female nautilus without the shell. "a, Muscular band passing…

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom; c.ch, Coelomic epithelium (yellow cells); cg, glandular cells; cl, Muscle cells of lateral line; cp, Pigment cells; ep, Ectoderm; g, Nerve cord; m, Intestine; mc, Circular muscle; ml, Longitudinal muscle; vd, Dorsal vessel; ww, Ventral vessel." (Britannic, 1910)

Sectional View of Acanthobdella

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom;…

"Ground Plan of the Colosseum at Rome, with representation of the Tiers of Seats, and of the Substructure. The shape of the amphitheatre was borrowed from that of the theatre. Since no stage was necessary, and with a view to securing as many rows of seats as possible, the semicircular form of the theatre was done away with, and the whole became a circle, or rather an ellipse, which was afterwards the recognized shape for all buildings of this nature, whether at Rome or in the provinces."

Ground Plan of the Colosseum

"Ground Plan of the Colosseum at Rome, with representation of the Tiers of Seats, and of the Substructure.…

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom; c.ch, Coelomic epithelium (yellow cells); cg, glandular cells; cl, Muscle cells of lateral line; cp, Pigment cells; ep, Ectoderm; g, Nerve cord; m, Intestine; mc, Circular muscle; ml, Longitudinal muscle; vd, Dorsal vessel; ww, Ventral vessel; cn, nerve cord; nf, parts of nephridium; on, external opening of nephridium; ov, ova; t, testis." (Britannica, 1910)

Sectional View of Acanthobdella

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom;…

"Section and Interior View of the five-aisled Basilica of S. Pietro at Rome, before its restoration. Large basilicas sometimes have as many as five aisles — namely, a main-aisle in the middle, and two lower aisles on each side."

Old St. Peter's Basilica

"Section and Interior View of the five-aisled Basilica of S. Pietro at Rome, before its restoration.…

"Profile and view from beneath of the Rafters in the Christian Basilica of San Miniato at Florence. The roofing of the basilicas consisted of beams with a flat paneling, which was richly gilt in earlier times, or the rafters of the timberworks were left without a casing, and were ornamented with colorful embellishments."

Profile of San Miniato al Monte

"Profile and view from beneath of the Rafters in the Christian Basilica of San Miniato at Florence.…

The obverse side of an écu of James V of Scotland, a Scotch gold coin also called a crown.

Écu, Obverse

The obverse side of an écu of James V of Scotland, a Scotch gold coin also called a crown.

The reverse side of an écu of James V of Scotland, a Scotch gold coin also called a crown.

Écu, Reverse

The reverse side of an écu of James V of Scotland, a Scotch gold coin also called a crown.

The obverse side of the écu d'or of Charles VI, king of France.

Écu, Obverse

The obverse side of the écu d'or of Charles VI, king of France.

The reverse side of the écu d'or of Charles VI, king of France.

Écu, Reverse

The reverse side of the écu d'or of Charles VI, king of France.

Edwardsia beautempsi is a species of sea anemone that lives freely in tubes in the sand, unattached.

Sea Anemone

Edwardsia beautempsi is a species of sea anemone that lives freely in tubes in the sand, unattached.

The Electric Eel (Electrophorus electricus) is a fish in the Gymnotidae family of naked-back knifefishes.

Electric Eel

The Electric Eel (Electrophorus electricus) is a fish in the Gymnotidae family of naked-back knifefishes.

An illustration of the side-view of the fumitory flower Fumaria is a genus of about fifty annual herbaceous flowering plants in the family Fumariaceae, native to temperate Europe and Asia, though some species are weedy or adventive in North and South America, Australia, etc. It is closely allied to Corydalis (from which it differs chiefly in having single-seeded fruits), and some botanists combine the two genera. The common name is fumitory.

Fumitory (Side-view)

An illustration of the side-view of the fumitory flower Fumaria is a genus of about fifty annual herbaceous…

View of Mt. Stromboli from the northwest.

Mt. Stromboli

View of Mt. Stromboli from the northwest.

Bird's eye view of the Gulf of Santorin, during the volcanic eruption of February 1866.

Gulf of Santorin

Bird's eye view of the Gulf of Santorin, during the volcanic eruption of February 1866.

View of a part of the Val-del-Bove with parasitic cones and steep lava streams.

Val-del-Bove

View of a part of the Val-del-Bove with parasitic cones and steep lava streams.

View of the volcano Mount Pelée, on Martinique, a French overseas department.

Mount Pelée

View of the volcano Mount Pelée, on Martinique, a French overseas department.

View of the volcano Mount Pelée, on Martinique, a French overseas department.

Mount Pelée

View of the volcano Mount Pelée, on Martinique, a French overseas department.

"Suppose we have a pipe A B laid in a horizontal position so that the centre line is exactly at the same level all along the pope, and differences of level may be neglected. Let water be delivered b this pipe at a steady from a reservoir provided with a constant supply which keeps the free surface level always the same. If the pipe A B is of uniform sectional area throughout, and is at all points offers a uniform frictional resistance to the flow of the water, the pressure will gradually become less at points along it more and more distanct from the reservoir. This is no lonfer the case when the pipe is larger at one place than another, as shown in the [figure]." (Britannica, 1891)

Water Flow in Pipes

"Suppose we have a pipe A B laid in a horizontal position so that the centre line is exactly at the…

"An instrument for observing or detecting the existence of free electricity, and, in general, for determining its kind. ... The simplest electroscope consists of pith-balls suspended by silk threads." -Whitney, 1911

Pith-Ball Electroscope

"An instrument for observing or detecting the existence of free electricity, and, in general, for determining…

"An instrument for observing or detecting the existence of free electricity, and, in general, for determining its kind. ... Quadrant electroscope, a form of pith-ball electroscope which serves to measure roughly the degree of electrification by the rise of the pith-ball as indicated by the motion of the rod carrying it on a graduated semicircle." -Whitney, 1911

Quadrant Electroscope

"An instrument for observing or detecting the existence of free electricity, and, in general, for determining…

"An instrument for observing or detecting the existence of free electricity, and, in general, for determining its kind. ... In Volta's condensing electroscope, in place of the gilt knob there is a flat metal plate upon which rests another similar plate, which may be removed by an insulating handle." -Whitney, 1911

Condensing Electroscope

"An instrument for observing or detecting the existence of free electricity, and, in general, for determining…

The Egyptian Free-Tailed Bat (Tadarida aegyptiaca) is a species of bat in the Molossidae family of free-tailed bats.

Egyptian Free-Tailed Bat

The Egyptian Free-Tailed Bat (Tadarida aegyptiaca) is a species of bat in the Molossidae family of free-tailed…

An illustration of a section of the reverberatory furnace. A reverberatory furnace is a metallurgical or process furnace that isolates the material being processed from contact with the fuel, but not from contact with combustion gases. The term reverberation is used here in a generic sense of rebounding or reflecting, not in the acoustic sense of echoing.

Sectional View of a Reverberatory Furnace

An illustration of a section of the reverberatory furnace. A reverberatory furnace is a metallurgical…

An illustration of a longitudinal sectional view of the valerian flower. Valerian is a hardy perennial flowering plant, with heads of sweetly scented pink or white flowers. The flowers are in bloom in the northern hemisphere from June to September. Valerian was used as a perfume in the sixteenth century.

Valerian Flower (Longitudinal Section)

An illustration of a longitudinal sectional view of the valerian flower. Valerian is a hardy perennial…

An illustration of a longitudinal section view of a disk-floret of the cornflower. Centaurea cyanus ('Cornflower, Bachelor's button, Basket flower, Bluebottle, Boutonniere flower, Hurtsickle) is a small annual flowering plant in the family Asteraceae, native to Europe.

Disk-floret of a Cornflower (Longitudinal

An illustration of a longitudinal section view of a disk-floret of the cornflower. Centaurea cyanus…

An longitudinal section view of a disk-floret of the senecio flower. Senecio is a genus of the daisy family (Asteraceae) that includes ragworts and groundsels. The flower heads are normally rayed, completely yellow, and the heads are borne in branched clusters. Though of late the genus has been reviewed and split up, it still contains a vast number of species (about 1,500) of extremely wide form including leaf succulents, stem and tuber succulents, annuals, perennials, aquatic forms, climbers, shrubs and small trees. Some species produce natural pesticides (especially alkaloids) to deter or even kill animals that would eat them.

Disk-floret of the Senecio (Longitudinal Section)

An longitudinal section view of a disk-floret of the senecio flower. Senecio is a genus of the daisy…

The dorsal view of the larva of the Tawny Emperor (Asterocampa clyton), a brush-footed butterfly.

Emperor Butterfly Larva

The dorsal view of the larva of the Tawny Emperor (Asterocampa clyton), a brush-footed butterfly.

The lateral view of the pupa of the Tawny Emperor (Asterocampa clyton), a brush-footed butterfly.

Emperor Butterfly Pupa

The lateral view of the pupa of the Tawny Emperor (Asterocampa clyton), a brush-footed butterfly.

"Inside View of Shield, showing Enarme, or Gear. Enarmer, provide, as a shield, with straps." -Whitney, 1911

Enarme

"Inside View of Shield, showing Enarme, or Gear. Enarmer, provide, as a shield, with straps." -Whitney,…

Scilla (squill) is a genus of bulb-forming perennial herbs in the Hyacinthaceae. The 90-odd species are found in woodlands, subalpine meadows, and seashores across the Old World. Their flowers are usually blue, but white, pink, and purple types are known; most flower in early spring, but a few are autumn-flowering.

Scilla

Scilla (squill) is a genus of bulb-forming perennial herbs in the Hyacinthaceae. The 90-odd species…

The Northern Plains Gray Langur (Semnopithecus entellus) is a primate in the Cercopithecidae family of Old World monkeys.

Gray Langur

The Northern Plains Gray Langur (Semnopithecus entellus) is a primate in the Cercopithecidae family…

"Anterior View, Distal End, of Right Humerus of a Man. H, humerus; epc, epicondyle, or external supracondyloid protuberance; ept, epitrochlea, or internal supracondyloid protuberance; cp, capitellum, or convex articular suface for head of radius; tr, trochlea, or transversely concave articular surface for the ulna; epc and cp are together the ectocondyle, and ept and tr are together the entocondyle." -Whitney, 1911

Humerus

"Anterior View, Distal End, of Right Humerus of a Man. H, humerus; epc, epicondyle, or external supracondyloid…

"Part of Epiphyllospermous Frond. In botany, bearing the fruit or spores on the back of the leaves or fronds, as ferns." -Whitney, 1911

Epiphyllospermous Frond

"Part of Epiphyllospermous Frond. In botany, bearing the fruit or spores on the back of the leaves or…

Episema were used in Greece as a symbol for a country, region, or used on a shield or badge. This episemon depicts a lion's head with a fish in its mouth.

Episemon

Episema were used in Greece as a symbol for a country, region, or used on a shield or badge. This episemon…

Also known as fish lice, this is a species of copepod, a parasitic crustacean. "Female of Chondracathus gibbosus, enlarged; and example of the crustaceous Epizoa. A, lateral view." -Whitney, 1911

Copepod

Also known as fish lice, this is a species of copepod, a parasitic crustacean. "Female of Chondracathus…

Also known as fish lice, this is a species of copepod, a parasitic crustacean. "Female of Chondracathus gibbosus, enlarged; and example of the crustaceous Epizoa. B, ventral view; a, head; b, c, appendages; d, d, mediodorsal processes; e, e, medioventral processes; f, i, h, lateral processes; g, ovisacs; k, terminal segment; l, minute male lodged in vulva of female; m, n, mediodorsal ovarian tubes; p, lateral ovarian tubes; o, o, oviduct; 2, 3, antennules; 4, 5, 6, antennae, gnathites." -Whitney, 1911

Copepod

Also known as fish lice, this is a species of copepod, a parasitic crustacean. "Female of Chondracathus…

"A Lion's Head Erased. In heraldry, represented as having been forcibly torn off, the separated parts being left jagged, as opposed to couped." -Whitney, 1911

Erased

"A Lion's Head Erased. In heraldry, represented as having been forcibly torn off, the separated parts…

An illustration of a microscopic view under the surface of a young prothallus: pr, prothallus; w, root-hairs; an, antheridia; ar, archegonia. A prothallium, or prothallus is usually a pteridophyte, i.e. spore-bearing plant, (almost exclusively ferns) in gametophyte stage in the alternation of generations cycle.

Young Prothallus of Fern

An illustration of a microscopic view under the surface of a young prothallus: pr, prothallus; w, root-hairs;…

An illustration of the anteridium of a bracken. An antheridium (plural: antheridia) is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). Brackens (Pteridium) are a genus of about ten species of large, coarse ferns, in the family Dennstaedtiaceae. The genus has probably the widest distribution of any fern genus in the world, being found on all continents except Antarctica and in all environments except for hot and cold deserts. Therefore it is considered to have a cosmopolitan distribution.

Antheridium of Bracken

An illustration of the anteridium of a bracken. An antheridium (plural: antheridia) is a haploid structure…

The Southern Muriqui (Brachyteles arachnoides) is a wooly spider monkey in the Atelidae family of New World monkeys.

Southern Muriqui

The Southern Muriqui (Brachyteles arachnoides) is a wooly spider monkey in the Atelidae family of New…

The ventral and dorsal view of the pupa of Erotylus boisduvali, a fungus beetle.

Fungus Beetle Pupa

The ventral and dorsal view of the pupa of Erotylus boisduvali, a fungus beetle.

Portrait Sir Galahad detail from the painting by George Frederick Watts.

Sir Galahad

Portrait Sir Galahad detail from the painting by George Frederick Watts.

This Assyrian bucket is designed with a cord handle and terminates at the bottom with a lion mask. It was used to transport water.

Assyrian Bucket

This Assyrian bucket is designed with a cord handle and terminates at the bottom with a lion mask. It…