Illustrations of a segment, a ray, and a line that can be used when providing definitions.

Definitions, Segment, Ray, Line

Illustrations of a segment, a ray, and a line that can be used when providing definitions.

Common skate (ray). The skates and rays have a broad body, partly due to the merging of the body into the large, horizontally flattened pectoral fins.

Skate

Common skate (ray). The skates and rays have a broad body, partly due to the merging of the body into…

The jaws and teeth of the common skate (ray).

Skate

The jaws and teeth of the common skate (ray).

Mouth and gill slits of the common skate (ray).

Skate

Mouth and gill slits of the common skate (ray).

"It is very voracious, and grows to large size. Found in the European and American waters" — Goodrich, 1859

Skate

"It is very voracious, and grows to large size. Found in the European and American waters" — Goodrich,…

"Skate, a common name for several species of the genus Raia. The members of this genus are characterized by the two dorsal fins on the tails and the absence of a tail spine, and by the pelvic fins being deeply notched."—Finley, 1917

Common Skate

"Skate, a common name for several species of the genus Raia. The members of this genus are characterized…

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence of which gives name to the acanthopterygian fishes; a spinous fin-ray, as distinguished for a soft ray."
<p>Illustration of the ventral fin of the acanthopterygian fish.

One Spine on the Ventral Fin of a Bony Fish

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence…

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence of which gives name to the acanthopterygian fishes; a spinous fin-ray, as distinguished for a soft ray."
<p>Illustration of the anal fin of the acanthopterygian fish.

Three Spines on the Anal Fin of a Bony Fish

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence…

"Condensing Straight Prisms.&mdash;These, either by reflexion or refraction or both, cause a ray fr proceeding in any compass bearing from a fixed light apparatus AA to emerge in the direction, e.g., parallel to the corresponding ray fb, which proceeds in the same compass bearing from another part of the apparatus and so of any other ray fc which is bent parallel to the ray fa." &mdash;The Encyclopedia Britannica, 1910

Straight Prisms

"Condensing Straight Prisms.—These, either by reflexion or refraction or both, cause a ray fr…

"When the moon psses between the Earth and Sun, there happens an eclipse of the Sun, because then the Moon's shadow falls upon the Earth. A total eclipse of the Sun happens often, but when it occurs, the total obscurity is confined to a small part of the Earth; since the dark portion of the Moon's shadow never exceeds 200 miles in diameter on the Earth. But the Moon's partial shadow, or penumbra, may cover a space on the Earth of more than 4,000 miles in diameter, within all which space the Sun will be more or less eclipsed. When the penumbra first touches the Earth, the eclipse begins at that place, and ends when the penumbra leaves it. But the eclipse will be total only where the dark shadow of the Moon touches the earth." &mdash;Comstock, 1850

Sun Eclipse

"When the moon psses between the Earth and Sun, there happens an eclipse of the Sun, because then the…

"The prevailing color of the upper part, which is rough and with small points, is dark brown, the under part white, as is the case with most species of ray. It is two to three feet long." &mdash; Goodrich, 1859

Thornback

"The prevailing color of the upper part, which is rough and with small points, is dark brown, the under…

"Condensing Twin Prism Light.&mdash;Part of the Lamiash light in the Firth of Clyde. Its action will be easily understood by the numbers shown on the diagram." &mdash;The Encyclopedia Britannica, 1910

Twin Prism

"Condensing Twin Prism Light.—Part of the Lamiash light in the Firth of Clyde. Its action will…

"Umbra and Penumbra. A solar eclipse, with the penumbra, d, c, and the umbra or dark shadow is seen here. When the Moon is at its greatest distance from the Earth, its shadow m o, sometimes terminates, before it reaches the Earth, and then an observer standing directly under the point o, will see the outer edge of the Sun, forming a bright ring around the circumference of the Moon, thus forming an annular eclipse." &mdash;Comstock, 1850

Umbra

"Umbra and Penumbra. A solar eclipse, with the penumbra, d, c, and the umbra or dark shadow is seen…