Cilia

(Lat. cilium, an eyelash). Microscopic, hair-like filaments, which have the power of lashing backwards and forwards, thus creating currents in the surrounding or contiguous fluid, or subserving locomotion in the animal which possesses them.

Ciliograda

(Lat. cilium ; and gradior, I walk). Synonymous with Ctenophora, an order of Actinozoa.

Cinclides

(Gr. kigklis, a lattice). Special apertures in the column walls of some Sea-anemones (Actinidae), which probably serve for the emission of the cord-like " craspeda."

Cirri

(Lat. cirrus, a curl). Tendril-like appendages, such as the feet of Barnacles, and Acorn-shells (Cirripedes), the lateral processes on the arms of Brachiopoda, etc.

Cirriferous or Cirrigerous

Carrying cirri.

Cirripedia, Cirrhipedia, or Cirrhopoda

(Lat. cirrus, a curl; and pes, a foot). A sub-class of Crustacea with curled jointed feet.

Cirrostomi

(Lat. cirrus, a tendril; Gr. stoma, mouth). Sometimes used to designate the Pharyngobranchii.

Cladocera

(Gr. klados, a branch; keras, a horn). An order of Crustacea with branched antennae.

Clavate

(Lat. clavus, a club). Club-shaped.

Clavicle

(Lat. clavicula, a little key). The "collar-bone," forming one of the elements of the pectoral arch of Vertebrates.

Cloaca

(Lat. a sink). The cavity into which the intestinal canal and the ducts of the generative and urinary organs open in common, in some Invertebrates (e.g., in Insects), and also in many Vertebrate animals.

Clypeiform

(Lat. clypeus, a shield; and forma, shaped). Shield-shaped; applied, for example, to the carapace of the King-crab.

Cnidae

(Gr. knide, a nettle). The urticating cells or " thread-cells" whereby many Cozlenterate animals obtain their power of stinging.

Coccoliths

(Gr. kokkos, a berry; lithos, stone). Minute oval or rounded bodies, which are found either free or attached to the surface of cocco-spheres, and which are probably of vegetable origin.

Coccospheres

(Gr. kokkos ; and sphaira, a sphere). Spherical masses of sarcode, enclosed in a delicate calcareous envelope, and bearing coccoliths upon their external surface.

Coccygeal

Connected with the coccyx.

Coccyx

(Gr. kokkux, a cuckoo). The terminal portion of the spinal column in man, so called from its resemblance to a cuckoo's beak.

Cocoon

(French, cocon, the cocoon of the silk-worm; connected with Fr. coque, shell, which is derived from the Lat. concha). The outer covering of silky hairs with which the pupa or chrysalis of many insects is protected. The chitinons capsules in which Leeches and Earth-worms deposit their eggs. The silken cases which Spiders weave for their eggs.

Codonostoma

(Gr. kodon, a bell; stoma, mouth). The aperture or mouth of the disc (nectocalyx) of a Medusa, or of the hell (gonocalyx) of a medusi-form gonophore.