Crustaceans. Belonging to the crab or lobster family, &c.
Cryptogamous. Plants without apparent flowers.
Crystal. The regular form in which a mineral is presented when that form can be described mathematically. A mineral is said to be crystalline when its atoms are arranged with reference to some definite form.
Ctenacanthus. Belonging to the Placoids.
Ctenoids. Fishes with comb-shaped scales.
Ctenoptychius. A fish of the chalk formation.
Culm. An impure kind of coal.
Cumbrian. Occurring in Cumberland. The “Cumbrian System” of Prof. Sedgwick is a part of the Silurian series of the Lake district of Cumberland and Westmoreland.
Cycadeæ. Fossil plants of the coal-measures.
Cyclas. A small bivalve shell recent and fossil.