294 MANUAL OP ZOOLOGY. 



medium by which the separate polypites of a compound Hydrozoon are 



connected together. 

 COLEOPTERA (Gr. koleos, a sheath; pteron, wing). The order of Insects 



(Beetles) in which the anterior pair of wings are hardened, and serve as 



protective cases for the posterior pair of membranous wings. 

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



to the jointed stem or peduncle of the stalked Crinoids. 

 COLUMELLA (Lat. diminutive of columna, a column). In Conchology, the 



central 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. 

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



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

 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 



Lamellibranchiata. 



COPEPODA (G-r. kope, an oar ; poda, feet). An order of Crustacea. 

 CORALLIGENOUS. Producing a corallum. 

 CORALLITE. The corallum secreted by an Actinozoon 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 Actinozoon commonly called a ' coral.' 

 CORIACEOUS (Lat. corium, hide). Leathery. 

 CORTICAL LAYBR. 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.' 

 COSTJE (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 thecae, and mark the position of the 



septa within. 

 CRASPEDA (G-r. 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 Echinodermata, 



comprising forms which are usually stalked, and sometimes resemble 



lilies in shape. 



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 ; Jcustis, a bag, or cyst). The sense-organ 



(probably auditory) which occurs in the CtenopJiora. 

 CTENOPHORA (Gr. kteis, a comb; &nd.phero, I carry). An order of Actinczoa, 



comprising oceanic creatures, which swim by means of ' ctenophores,' or 



bands of cilia arranged in comb-like plates. 

 CUTICLE (Lat. cuticula, dim. of cut-is, skin). The pellicle which forms the 



outer layer of the body amongst the Infusoria. 

 CYST (Gr. kustis, a bladder or bag). A sac, or vesicle. 

 CYSTICA. The embryonic forms (scolices) of certain intestinal worms (tape- 

 worms), which were described as a distinct order, until their true nature 



was discovered. 



