"Actinomma Asteracanthion, a Radiolarian with a limited number of specialized radii (axes), symmetrically arranged about the center. A, whole animal with portion of two spheres of shell removed. B, section, showing relation of the protoplasm to the skeleton. n, nucleus; p, protoplasm; sk., skeleton." — Galloway

Actinomma Asteracanthion

"Actinomma Asteracanthion, a Radiolarian with a limited number of specialized radii (axes), symmetrically…

Bones of the Ankle and Foot. Labels: m, metatarsal bones; p, phalanges; ca, os calcis, or heel bone.

Bones of the Ankle and Foot

Bones of the Ankle and Foot. Labels: m, metatarsal bones; p, phalanges; ca, os calcis, or heel bone.

An illustration of the skeletal fossil of Archaeopteryx, the earliest and most primitive bird known. Archaeopteryx lived in the late Jurassic Period around 155–150 million years ago, in what is now southern Germany during a time when Europe was an archipelago of islands in a shallow warm tropical sea, much closer to the equator than it is now.

Archaeopteryx Fossil

An illustration of the skeletal fossil of Archaeopteryx, the earliest and most primitive bird known.…

"View from above of the Atlas, the first cervical vertebra."—Finley, 1917

Atlas

"View from above of the Atlas, the first cervical vertebra."—Finley, 1917

"Side view of the axis, the second cervical vertebra."—Finley, 1917

Axis

"Side view of the axis, the second cervical vertebra."—Finley, 1917

The bat genus Nyctalus (Noctule bats) are Evening bats. They are distributed in the temperate and subtropical areas of Europe, Asia and North Africa.

Skeleton and Wing Membranes of the Noctule Bat

The bat genus Nyctalus (Noctule bats) are Evening bats. They are distributed in the temperate and subtropical…

A bird resting on the ground, near some bones.

Bird

A bird resting on the ground, near some bones.

"Right shoulder-girdle or scapular arch of fowl, showing hp, the hypoclidium; f, furculum; Co, coracoid; Sc, scapula; gl, glenoid." -Whitney, 1911

Bird Scapula

"Right shoulder-girdle or scapular arch of fowl, showing hp, the hypoclidium; f, furculum; Co, coracoid;…

Skeleton of a bird. 1: The head. 2: Cervical Vertebrae. 3: Dorsal and lumbar vertebrae. 4: Scapula. 5: Clavicle. 6: Coracoid bone. 7: Sternum. 8: Humerus. 9: Radius. 10: Ulna. 11: Carpus. 12: Metacarpus. 13: Phalanges (fingers). 14: Femur. 15: Tibia. 16: Fibula. 17: Tarsus. 18: Metatarsus. 19: Phalanges (toes).

Bird Skeleton

Skeleton of a bird. 1: The head. 2: Cervical Vertebrae. 3: Dorsal and lumbar vertebrae. 4: Scapula.…

Back view of the body and outline of skeleton and covering.

Back View of the Body

Back view of the body and outline of skeleton and covering.

Front view of the body and outline of skeleton and covering.

Front View of the Body

Front view of the body and outline of skeleton and covering.

"Skull of Cat (Felis catus), showing the following bones, viz. : na, nasal; pm, premaxillary; m, maxillary; l, lacrymal; f, frontal; j, jugal; pa, palatine; p, parietal; sq, squamosal; ip, interparietal; so, supra-occipital; eo, exoccipital (the line leads to the occipital condyle); t, tympanic bulla; smf, stylomastoid foramen; mf, mental foramen; c, coronoid process of mandible; ar, ascending ramus of mandible; hr, horizontal ramus of mandible; an, angle of jaw." -Whitney, 1911

Domestic Cat Skull

"Skull of Cat (Felis catus), showing the following bones, viz. : na, nasal; pm, premaxillary; m, maxillary;…

A cervical vertebra of the spine, inferior surface. Labels: 1, spinous process, slightly bifid; 4, transverse process; 5, articular process, inferior surface. Below the arch, or hollow portion, is seen the solid portion, or body.

Human Cervical Vertebra Bone

A cervical vertebra of the spine, inferior surface. Labels: 1, spinous process, slightly bifid; 4, transverse…

"The skeleton of the Chacma Baboon." — Encyclopedia Britanica, 1893

Chacma Baboon

"The skeleton of the Chacma Baboon." — Encyclopedia Britanica, 1893

The human clavicle bone (anterior portion of the shoulder girdle).

The Human Clavicle

The human clavicle bone (anterior portion of the shoulder girdle).

Skeleton of the cow. 1: Frontal bone of the head. 2: Upper jaw, superior maxillary. 3: Lower jaw, inferior maxillary. 4: Cervical vertebrae. 5: Dorsal vertebrae. 6: Lumbar vertebrae. 7: Sacral vertebrae. 8: Caudal vertebrae. 9: Scapula. 10: Humerus 11: Radius and ulna. 12: Carpus. 13: Metacarpus. 14: Phalanges (toes). 15: Femur. 16: Tibia. 17: Tarsus. 18: Metatarsus. 19: Phalanges.

Cow Skeleton

Skeleton of the cow. 1: Frontal bone of the head. 2: Upper jaw, superior maxillary. 3: Lower jaw, inferior…

The Astrologer, from Hans Holbein's series of engravings, Dance of Death.

Dance of Death, The Astrologer

The Astrologer, from Hans Holbein's series of engravings, Dance of Death.

The King, from Hans Holbein's series of engravings, Dance of Death.

Dance of Death, The King

The King, from Hans Holbein's series of engravings, Dance of Death.

The Pedlar, from Hans Holbein's series of engravings, Dance of Death.

Dance of Death, The Pedlar

The Pedlar, from Hans Holbein's series of engravings, Dance of Death.

The Queen, from Hans Holbein's series of engravings, Dance of Death.

Dance of Death, The Queen

The Queen, from Hans Holbein's series of engravings, Dance of Death.

"The bones in the extremities of this the fleetest of quadrupeds are inclined very obliquely towards each other, and towards the scapular and iliac bones. This arrangement increases the leverage of the muscular system and confers great rapidity on the moving parts."—Pettigrew, 1874

Skeleton of the Deer

"The bones in the extremities of this the fleetest of quadrupeds are inclined very obliquely towards…

"Restoration of Dinoceras Mirabile." —The Encyclopedia Britannica, 1903

Dinoceras Mirabile

"Restoration of Dinoceras Mirabile." —The Encyclopedia Britannica, 1903

A restored skeleton of <em>Uintathcrium (Dinoceras) mirabile.</em>

Dinoceras Skeleton

A restored skeleton of Uintathcrium (Dinoceras) mirabile.

An illustration of a Diplodocus skeleton and the caudal vertebrae (A and B). Diplodocus is a genus of diplodocid sauropod dinosaur whose fossils were first discovered in 1877 by S. W. Williston. It lived in what is now western North America at the end of the Jurassic Period. Diplodocus is one of the more common dinosaur fossils found in the Upper Morrison Formation, a sequence of shallow marine and alluvial sediments deposited about 150 to 147 million years ago, in what is now termed the Kimmeridgian and Tithonian stages.

Diplodocus

An illustration of a Diplodocus skeleton and the caudal vertebrae (A and B). Diplodocus is a genus of…

Illustration of a dodo bird skeleton. The dodo (Raphus cucullatus) was a flightless bird endemic to the Indian Ocean island of Mauritius. Related to pigeons and doves, it stood about a meter tall, weighing about 20 kilograms (44 lb), living on fruit and nesting on the ground.

Dodo Skeleton

Illustration of a dodo bird skeleton. The dodo (Raphus cucullatus) was a flightless bird endemic to…

Side view of the dorsal vertebra.

Dorsal vertebra

Side view of the dorsal vertebra.

"Skeleton of Dugong: In which the pelvis is a mere bony ring." &mdash; Chambers, 1881

Dugong Skeleton

"Skeleton of Dugong: In which the pelvis is a mere bony ring." — Chambers, 1881

The skeleton of a dugong, one of four living species in the order Sirenia.

Skeleton of the Dugong

The skeleton of a dugong, one of four living species in the order Sirenia.

"The skeleton lay on the left side with knees drawn up and hands raised to the head. About it were various articles of food and vessels of pottery."&mdash;Webster, 1913

A Prehistoric Egyptian Tomb

"The skeleton lay on the left side with knees drawn up and hands raised to the head. About it were various…

The skeleton of an elasmosaurus, a dinosaur in the order of plesiosaurs.

Elasmosaurus Skeleton

The skeleton of an elasmosaurus, a dinosaur in the order of plesiosaurs.

The fossilized skeleton of an elephant.

Fossil elephant

The fossilized skeleton of an elephant.

The fossilized skeleton of an elk.

Fossilized elk

The fossilized skeleton of an elk.

Ethmoid bone, posterior surface. The ethmoid bone is an exceedingly light, spongy bone, placed between the two orbits and at the root of the nose, contributing to form a part of each of these cavities. Label: 2, cribriform, or perforated plate.

Ethmoid Bone of the Human Skull

Ethmoid bone, posterior surface. The ethmoid bone is an exceedingly light, spongy bone, placed between…

"The <em>femur</em>, or thigh bone, the largest and heaviest bone in the body, reaches from the hip to the knee. It has a rounded head, which fits into the cuplike cavity in the hip bone which has already been mentioned." &mdash; Blaisedell, 1904

Femur

"The femur, or thigh bone, the largest and heaviest bone in the body, reaches from the hip…

The Femur (upper leg bone) is the longest, largest, and strongest bone in the skeleton. Labels: b, rounded head; n, neck; gtr, greater trochanter; ltr, lesser trochanter.

Human Femur Bone

The Femur (upper leg bone) is the longest, largest, and strongest bone in the skeleton. Labels: b, rounded…

"Anterior View of Human Right Femur. ec, external condyle; etu, external tuberosity; ic, internal condyle; itu, internal tuberosity; ltr, lesser trochanter; gtr, great trochanter; h, head; n, neck." -Whitney, 1911

Anterior View of Human Right Femur

"Anterior View of Human Right Femur. ec, external condyle; etu, external tuberosity; ic, internal condyle;…

This is the skeleton of an angler fish (Lophius piscatorius).

Angler Fish

This is the skeleton of an angler fish (Lophius piscatorius).

The internal border of the skeleton of the foot.

Foot Skeleton

The internal border of the skeleton of the foot.

The external border of the skeleton of the foot.

Foot Skeleton

The external border of the skeleton of the foot.

"The foot is built in the form of a half-dome or half-arch. This is to afford a broad, strong support surface for the support of the weight of the body. The bones of the toes and the heel form the piers, while the little bones wedged in between the metatarsal bones and the heel make up the keystone of the arch. This arch gives a certain amount of spring and elasticity to the feet, and hence it is of the upmost importance in preventing jars and jolts." — Blaisedell, 1904

Bones of the Foot

"The foot is built in the form of a half-dome or half-arch. This is to afford a broad, strong support…

An illustration of the skeleton of a kangaroo's right hind foot.

Kangaroo Foot

An illustration of the skeleton of a kangaroo's right hind foot.

The skeleton of a frog.

Frog skeleton

The skeleton of a frog.

Frontal bone of the human skull, outer surface. The frontal bone forms the forehead, roof of the orbital cavities, and the nasal cavity. Labels: 1, frontal eminence; 7, roof of orbital cavitiy; 10, orbital arch.

Frontal Bone of the Human Skull

Frontal bone of the human skull, outer surface. The frontal bone forms the forehead, roof of the orbital…

The skeletal structure of a gorilla.

Gorilla Skeleton

The skeletal structure of a gorilla.

"Pelvis of a young grouse, showing three distinct bones. Il,P, ilium, ischium, pubis. In front of former a dorsal vertebra protrudes." Elliot Coues, 1884

The Pelvis of a Young Grouse

"Pelvis of a young grouse, showing three distinct bones. Il,P, ilium, ischium, pubis. In front of former…

The skeleton of a haddock.

Haddock

The skeleton of a haddock.

An illustration of a sparrow-hawk's skeleton.

Skeleton of a Sparrowhawk

An illustration of a sparrow-hawk's skeleton.

"Skeleton of the horse." &mdash; Davison, 1906

Skeleton of a Horse

"Skeleton of the horse." — Davison, 1906

This illustration shows a side view of the human skeleton.

Human Skeleton

This illustration shows a side view of the human skeleton.

This illustration shows a front view of the human skeleton.

Human Skeleton

This illustration shows a front view of the human skeleton.

A human skeleton.

Human skeleton

A human skeleton.

"The <em>humerus</em>, a long, hollow bone, rests against a shallow socket on the shoulder blade. It is joined at the elbow to the bones of the forearm." &mdash; Blaisedell, 1904

Humerus

"The humerus, a long, hollow bone, rests against a shallow socket on the shoulder blade. It…

"The humerus, which moves freely by a globular head upon the scapula, forming the shoulder-joint." &mdash; Chambers' Encyclopedia, 1875

Humerus

"The humerus, which moves freely by a globular head upon the scapula, forming the shoulder-joint." —…

"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…

The human humerus bone, the longest and largest bone of the upper leg. Labels: a, rounded head; gt, greater tuberosity; lt, lesser tuberosity; b, groove for attachment of biceps tendon.

The Human Humerus

The human humerus bone, the longest and largest bone of the upper leg. Labels: a, rounded head; gt,…

The hyoid, os hyoides, or tongue bone, is an isolated, U-shaped bone lying in front of the throat, just above the Adam's apple; it supports the tongue, and give attachment to some of its numerous muscles.

Human Hyoid Bone

The hyoid, os hyoides, or tongue bone, is an isolated, U-shaped bone lying in front of the throat, just…

An illustration of an Ichthyosaurus skeleton. Ichthyosaurus is an extinct genus of ichthyosaur from the Early Jurassic (Hettangian - Sinemurian) of Europe (Belgium, England and Germany). It is among the best known ichthyosaur genera, with the Order Ichthyosauria being named after it. Ichthyosaurus was the first complete fossil to be discovered in the early 1800's by Mary Anning in England.

Archaeopteryx Skeleton

An illustration of an Ichthyosaurus skeleton. Ichthyosaurus is an extinct genus of ichthyosaur from…

Part of the skeletal structure of a lithisdid silicious sponge.

Jereiea Polystoma

Part of the skeletal structure of a lithisdid silicious sponge.

A simple complete joint, one type of movable articulation. The synovial membrane is represented by dotted lines. They have a secreting membrane placed between their opposing surfaces, which keeps them well lubricated and capable of free movement one upon the other.

A Simple Complete Joint

A simple complete joint, one type of movable articulation. The synovial membrane is represented by dotted…

A toothed, or dentated suture. This is one type of immovable articulation. It is found in the union of the cranial bones of the skull, such as the suture between the frontal and parietal bones.

Human Joint, Dentated Suture

A toothed, or dentated suture. This is one type of immovable articulation. It is found in the union…