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"Any two colors standing opposite each other are complementary to each other. If such colors are blended, the resultant is white light; if any two alternate color are blended, the resultant will be the color that appears between them in the figure." — Avery, 1895

Complementary color wheel

"Any two colors standing opposite each other are complementary to each other. If such colors are blended,…

Flat, pigmented, branched connective tissue cells from the sheath of a large blood vessel of a frog's mesentery. The pigment is not distributed uniformly throughout the substance of the larger cell, consequently some parts of it look blacker than others (uncontracted state). In the two smaller cells most of the pigment is withdrawn into the cell body, so that they appear smaller, blacker, and less branched.

Connective Tissue Cells from a Frog

Flat, pigmented, branched connective tissue cells from the sheath of a large blood vessel of a frog's…

"Diagram of a retinula of the central eye of a scorpion consisting of five retina-cells (ret), with adherent branched pigment cells (pig)." — The Encyclopedia Britannica, 1910

Retinula

"Diagram of a retinula of the central eye of a scorpion consisting of five retina-cells (ret), with…

"Rhabdom of the same, consisting of five confluent rhabdomeres." — The Encyclopedia Britannica, 1910

Rhabdom

"Rhabdom of the same, consisting of five confluent rhabdomeres." — The Encyclopedia Britannica,…