CRUSTACEA (Lat. crusta, a crust).  A class of Articulate animals, comprising Crabs, Lobsters, &c., characterised by the possession of a hard shell or crust, which they cast periodically.

CRYPTOGAMS (Gr. kruptos, concealed; gamos, marriage).  A division of plants in which the organs of reproduction are obscure and there are no true flowers.

CTENACANTHUS (Gr. kteis, a comb; akantha, a thorn).  A genus of fossil fishes, named from its fin-spines.

CTENOID (Gr. kteis, a comb; eidos, form).  Applied to those scales of fishes the hinder margins of which are fringed with spines or comb-like projections.

CURSORES (Lat. curro, I run).  An order of Aves, comprising birds destitute of the power of flight, but formed for running vigorously (e.g., the Ostrich and Emeu).

CUSPIDATE.  Furnished with small pointed eminences or “cusps.”

CYATHOCRINUS (Gr. kuathos, a cup; krinon, a lily).  A genus of Crinoids.

CYATHOPHYLLUM (Gr. kuathos, a cup; phullon, a leaf).  A genus of Rugose Corals.

CYCLOID (Gr. kuklos, a circle; eidos, form).  Applied to those scales of fishes which have a regularly circular or elliptical outline with an even margin.

CYCLOPHTHALMUS (Gr. kuklos, a circle; ophthalmos, eye).  A genus of fossil Scorpions.

CYCLOSTOMI (Gr. kuklos, and stoma, mouth).  Sometimes used to designate the Hag-fishes and Lampreys, forming the order Marsipobranchii.

CYPRAEA (a name of Venus).  The genus of Univalve Molluscs comprising the Cowries.

CYRTOCERAS (Gr. kurtos. crooked; keras, horn).  A genus of Tetrabranchiate Cephalopods.

CYSTIPHYLLUM (Gr. kustis, a bladder; phullon, a leaf).  A genus of Rugose Corals.

CYSTOIDEA (Gr. kustis, a bladder; eidos, form).  The “Globe-crinoids,” an extinct order of Echinodermata.

DADOXYLON (Gr. dadion, a torch; xulon, wood).  An extinct genus of Coniferous trees.

DECAPODA (Gr. deka, ten; podes, feet).  The division of Crustacea which have ten feet; also the family of Cuttle-fishes, in which there are ten arms or cephalic processes.

DECIDUOUS (Lat. decido, I fall off).  Applied to parts which fall off or are shed during the life of the animal.

DEINOSAURIA (Gr. deinos, terrible; saura, lizard).  An extinct order of Reptiles.

DEINOTHERIUM (Gr. deinos, terrible; therion, beast).  An extinct genus of Proboscidean Mammals.

DENDROGRAPTUS (Gr. dendron, tree; grapho, I write).  A genus of Graptolites.

DESMIDIAE.  Minute fresh-water plants, of a green colour, without a siliceous epidermis.

DIATOMACEAE (Gr. diatemno, I sever).  An order of minute plants which are provided with siliceous envelopes.