GLOSSARY. 579 



axis round which the whorls of a spiral univalve are wound. Amongst the 

 Actinozoa, it is the central axis or pillar which is found in the centre of the 

 thecse of many corals. 

 COLUMN. Applied to the cylindrical body of a Sea-anemone (Actinia] ; also 



to the jointed stem or peduncle of the stalked Crinoids. 

 COMMISSURAL (Lat. committo, I solder together). Connecting together ; 



usually applied to the nerve-fibres which unite different ganglia. 

 CONCHA (Lat. a shell). The external ear by which sounds are collected and 



transmitted to the internal ear. 

 CONCHIFERA (Lat. concha, a shell ; fero, I carry). Shell-fish. Applied in a 



restricted sense to the bivalve Molluscs, and used as a synonym for Lamelli- 



branchiata. 



CONDYLE (Gr. kondulos, a knuckle). The surface by which one bone articu- 

 lates with another. Applied especially to the articular surface or surfaces 



by which the skull articulates with the vertebral column. 

 CONIROSTRES (Lat. conus, a cone ; rostrum, a beak). The division of Perching 



birds with conical beaks. 



COPEPODA (Gr. kope, an oar ; poda, feet). An order of Crustacea. 

 CORACOLD (Gr. korax, a crow ; eidos, form). One of the bones which enters 



into the composition of the pectoral arch in Birds, Reptiles, and Mono- 



tremes. In most Mammals it is a mere process of tbe scapula, having, in 



man, some resemblance in shape to the beak of a crow. 

 CORALLIGENOUS. Producing a corallum. 

 CORALLITE. The corallum secreted by an Actinozodn which consists of a 



single polype ; or the portion of a composite corallum which belongs to, 



and is secreted by, an individual polype. 

 CORALLUM (from the Latin for Red Coral). The hard structures deposited in, 



or by, the tissues of an Actinozodn commonly called a " coral." 

 CORIACEOUS (Lat. corium, hide). Leathery. 

 CORPUS CALLOSUM (Lat. the "firm body"). The great band of nervous 



matter which unites the two hemispheres of the brain in the Mammals. 

 CORPUSCULATED (Lat. corpusculum, a little body or particle). Applied to 



fluids which, like the blood, contain floating solid particles or " corpuscles." 

 CORTICAL LAYER. The layer of consistent sarcode, which in the Infusoria 



encloses the chyme-mass, and is surrounded by the cuticle. Sometimes 



called the " parenchyma of the body." 

 COST.<E (Lat. costa, a rib). Applied amongst the Crinoidea to designate the 



rows of plates which succeed the inferior or basal portion of the cup 



(pelvis). Amongst the Corals the "costse" are vertical ridges which 



occur on the outer surface of the theca, and mark the position of the 



septa within. 



COSTAL (Lat. costa, a rib). Connected with the ribs. 

 CRANIUM (Gr. kmnion, the skull). The bony or cartilaginous case in which 



the brain is contained. 

 CRASPEDA (Gr. kraspedon, a margin or fringe). The long, convoluted cords, 



containing thread-cells, which are attached to the free margins of the 



mesenteries of a Sea-anemone. 

 CREPUSCULAR (Lat. crepusculum, dusk). Applied to animals which are active 



in the dusk or twilight. 

 CRINOIDEA (Gr. krinos, a lily ; eidos, form). An order of EcMnodermata, 



comprising forms which are usually stalked, and sometimes resemble lilies 



in shape. 



CROCODILIA (Gr. krokodeilos, a crocodile). An order of Reptiles. 

 CROP. A partial dilatation of the gullet, technically called " ingluvies." 

 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. 



CTENOCYST (Gr. kteis, a comb ; kuslis, a bag or cyst). The sense-organ (pro- 

 bably auditory) which occurs in the Ctenopliora. 

 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. 



