"(A fish that) had a compressed claviform body, posterior dorsal fins nearly opposite to the anus, prolonged upper tail-lobe, and well-developed spines in front of the fins."-Whitney, 1902

Acanthoclinus

"(A fish that) had a compressed claviform body, posterior dorsal fins nearly opposite to the anus, prolonged…

"The <em>Anoplotherium commune</em> was of the height of the wild boar, but its form was more elongated; it had a long and thick tail, like the kangaroo; and the feet had a divided hoof, or two large toes, like those of ruminating animals." &mdash; Goodrich, 1844

Anoplotherium Commune

"The Anoplotherium commune was of the height of the wild boar, but its form was more elongated;…

"The <em>Anoplotherium gracile</em> was of elegant proportions, resembling in size and form the gazelle, and must have lived after the manner of the deer and antelope." &mdash; Goodrich, 1844

Anoplotherium Gracile

"The Anoplotherium gracile was of elegant proportions, resembling in size and form the gazelle,…

A scene depicting a great auk, as well as razor-bills and puffins. The great auk is now extinct.

Great auk, razor-bills, and puffins

A scene depicting a great auk, as well as razor-bills and puffins. The great auk is now extinct.

"The trilobite's general form is shown in the annexed figure of the <em>Calymene Blumenbachii</em>; they possessed well-formed, compound, faceted eyes, which are frequently well-preserved in the fossil state. The body is usually divided into three regions, of which the first and last are commonly in the form of the semicircular plates, while the middle portion exhibits distinct segmentation, and by its flexibilty enabled the animal to double itself up in the manner of the common wood-louse." &mdash; Goodrich, 1859

Calymene

"The trilobite's general form is shown in the annexed figure of the Calymene Blumenbachii;…

1. Ichthyosaurus, 2. Teleosaurus, 3, 4, and 5. Plesiosaurus

Aquatic dinosaurs

1. Ichthyosaurus, 2. Teleosaurus, 3, 4, and 5. Plesiosaurus

Mauritius was the home of the now extinct dodo bird. The last bird was killed in 1681.

Dodo

Mauritius was the home of the now extinct dodo bird. The last bird was killed in 1681.

Mauritius was the home of the now extinct dodo bird. The last bird was killed in 1681.

Dodo

Mauritius was the home of the now extinct dodo bird. The last bird was killed in 1681.

The dodo, once a native of Mauritius. It was hunted to extinction by European sailors.

Dodo

The dodo, once a native of Mauritius. It was hunted to extinction by European sailors.

The fossilized skeleton of an elk.

Fossilized elk

The fossilized skeleton of an elk.

Isolated spicular bodies of an extinct silicious sponge. (<em>Epistomella clivosa</em>).

Epistomella Clivosa

Isolated spicular bodies of an extinct silicious sponge. (Epistomella clivosa).

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual reduction of the outer and enlargement of the middle toe (III). Orohippus (Eocene)." &mdash; Encyclopedia Britannica, 1893

Horse Foot

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual…

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual reduction of the outer and enlargement of the middle toe (III). Meschippus (Early Miocene)." &mdash; Encyclopedia Britannica, 1893

Horse Foot

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual…

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual reduction of the outer and enlargement of the middle toe (III). Miohippus and Anchitherium (Late Miocene)." &mdash; Encyclopedia Britannica, 1893

Horse Foot

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual…

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual reduction of the outer and enlargement of the middle toe (III). Hipparion and Pliohippus (Pliocene)." &mdash; Encyclopedia Britannica, 1893

Horse Foot

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual…

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual reduction of the outer and enlargement of the middle toe (III). Equus (Pleistocene)." &mdash; Encyclopedia Britannica, 1893

Horse Foot

"Successive stages of modification of the feet of extinct forms of horse-like animals, showin gradual…

The full-grown iguanodon is estimated to have reached lengths of thirty feet.

Iguanadon

The full-grown iguanodon is estimated to have reached lengths of thirty feet.

An extinct fossil colossal lizard found in the Wealden strata; so called from the resemblance of its teeth to those of the iguana.

Iguanodon

An extinct fossil colossal lizard found in the Wealden strata; so called from the resemblance of its…

An illustration of a maclurites, an extinct genus of snails.

Maclurites

An illustration of a maclurites, an extinct genus of snails.

An illustration of the operculum of the maclurites, an extinct genus of snails.

Operculum of Maclurites

An illustration of the operculum of the maclurites, an extinct genus of snails.

"Mastodon is an extinct genus of proboscideans, closely allied to the true elephants. The genus ranged in time from the middle of the Miocene period to the end of the Pliocene in the Old World, when they became extinct. In America several species survived to a late leistocene period. "&mdash;(Charles Leonard-Stuart, 1911)

Mastodon

"Mastodon is an extinct genus of proboscideans, closely allied to the true elephants. The genus ranged…

Mastodons or Mastodonts are members of the extinct genus Mammut of the order Proboscidea and form the family Mammutidae; they resembled, but were distinct from, the woolly mammoth, which belongs to the family Elephantidae. Mastodons were browsers, while mammoths were grazers.

Mastodon

Mastodons or Mastodonts are members of the extinct genus Mammut of the order Proboscidea and form the…

A pair of megalosauruses, with a group of pterodactyls in the background.

Megalosaurus and pterodactyls

A pair of megalosauruses, with a group of pterodactyls in the background.

The fossilized skeleton of a Megatherium.

Fossil Megatherium

The fossilized skeleton of a Megatherium.

"The <em>Palaeotherium magnum</em> was of the size of a horse, but thicker and more clumsy; its head was massive, and its legs and tail were short. It resembled a large tapir, but differed somewhat as to the teeth, and had one toe less on the fore-feet. Its height was probably from four to five feet; about equal, it is said, to that of the rhinoceros of Java. It was, no doubt, furnished with a short proboscis or trunk." &mdash; Goodrich, 1844

Palaeotherium magnum

"The Palaeotherium magnum was of the size of a horse, but thicker and more clumsy; its head…

"The <em>Palaeotherium minus</em> was smaller in size compared to the <em>Palaeotherium magnum</em>, probably not larger than a roe-buck, and of similar form to the tapir. It had light and slender limbs." &mdash; Goodrich, 1844

Palaeotherium minus

"The Palaeotherium minus was smaller in size compared to the Palaeotherium magnum,…

The extinct crested parrot of Mauritius.

Crested Parrot of Mauitius

The extinct crested parrot of Mauritius.

The extinct Phillip-Island parrot.

Philip Island Parrot

The extinct Phillip-Island parrot.

"Ectopistes migratorius. Passenger Pigeon. Wild Pigeon Adult: Upper parts, including head all around, slaty-blue, bright and pure on head and rump, shaded with olivaceous-gray on the back and wings; the back and sides of the neck glittering with golden and violet iridescence, the wing-coverts with velvety-clack spots. Below, from the throat, light purplish-chestnut, paler behind and fading into white on the lower belly and crissum. Tibiae, sides of body, and lining of wings like upper parts. Quills blackish, with rufous-white edging. Two middle tail-feathers blackish; others fading from pearly-bluish into white, their extreme bases with black and chestnut spots. Bill black; feet lake red, drying and undefinable color; iris orange; skin about eye red." Elliot Coues, 1884

Passenger Pigeon

"Ectopistes migratorius. Passenger Pigeon. Wild Pigeon Adult: Upper parts, including head all around,…

Once one of the most numerous bird species in the world, the common wild pigeon of the United States is now extinct.

Wild Pigeons

Once one of the most numerous bird species in the world, the common wild pigeon of the United States…

"So peculiar and strange is the structure of these animals, that the first specimen discovered was classed by one naturalist as a bird, by another as a species of bat, and by yet a third as a flying reptile." &mdash; Goodrich, 1844

Pterodactyle skeleton

"So peculiar and strange is the structure of these animals, that the first specimen discovered was classed…

An extinct subspecies of the zebra.

Quagga

An extinct subspecies of the zebra.

The extinct starling of Reunion.

Starling of Reunion

The extinct starling of Reunion.

"Tinoceras, or tinotherium, is a genus of mammals now extinct, found in the Eocene, and representing the order Dinocerata. The individuals were all large, some of them nearly equaling the elephants, while the brain was smaller than that of any living or fossil mammal."&mdash;(Charles Leonard-Stuart, 1911)

Tinoceras

"Tinoceras, or tinotherium, is a genus of mammals now extinct, found in the Eocene, and representing…