GLOSSARY. 365 



Cloaca (Lat. a sink). The oomnion cavity into Tvliich open the intestinal 



canal and the ducts of the generative and urinary organs in many Inverte- 

 brates and some Vertebrates. 

 CN1D.E (Gr. knidS, a nettle). The nrticating cells ("thread- cells") whereby 



many of the Coslenterala obtain their power of stinging. 

 Cocoon (Fr. cocon, the cocoon of the silk-worm). The outer covering of silky 



hairs with which the pupa or chrysalis of many insects is protected. 

 C(ELENTERATA (Gr. koilos, hollow ; enteron, the boweU. The sub-kingdom 



which includes the Hydrozoa and Acihiozoa^ the most typical members of 



Cuvier's division of the Hadiaia. 

 C(ENOSABC (Gr. koinos, common ; sarx, flesh). The common organised medium 



or stem by which the separate zooids of a compound //^(iroaooji ot Actinozolin 



are united together. 

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



(Beetles) in which the anterior wings are hardened, and forzn protective 



sheaths for the po.sterior membranous wings. 

 CoLUMBACEi (Lat. colmiiba, a dove). The subdivision of the Easorial Birds 



containing the Doves and Pigeons. 

 Condyle (Gr. kondulos, a knuckle). The surface by which one Itone is jointed 



or articulated to another. Applied especially to the articular surfaces by 



which the head is jointed to the vertebral column. 

 CoNiROSTRES (Lat. conus, a cone ; rostrwn, a beak). The division of Perching 



Birds with conical beaks. 

 CoPEPODA (Gr. kopi, an oar ; podes, feet). An order of Crustacea. 

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



.scapular arch in Birds, Reptiles, and Monotremata. In the majority of 



Mammalia it is a mere process of the scapula, and in Man its shape is some- 

 thing like that of the beak of a crow ; hence its name. 

 CoBALLlTE. The entire coral of a simple Actiriozoon, or the portion of a C07?i- 



ponnd coral which belongs to, and is secreted by, a single polype. 

 CORALLUM (Lat. for red coral). The hard structures deposited in or by the 



tissues of any Actinozoon — commonly called a " coral." 

 CoRPns CALLOSU.M (Lat. the " firm body "). The great band of nervous matter 



which unites the two hemispheres of the brain in the Mammalia. 

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



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

 Cortical layer (Lat. cortex, bark). Tlie layer of consistent sarcode which 



encloses the central " abdominal cavity" in the Infusoria a,ui is covered by 



the cuticle. 

 COHYNIDA (Gr. korunS, a club). An order of Hydroid Zoophytes. 

 Costal (Lat. casta, a rib). Connected witli the ribs. 

 Chanidm (Gr. kranion, 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, wliich are attached to the free margins of the mesen- 

 teries in a Sea-anemone. 

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



in the dusk or twilight. 

 Ceinoidea (Gr. krinos, a lily ; eidos, form). An order of Echinodermata 



comprising forms which are usually stalked, and sometimes resemble lilies 



in shape. 

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

 Crop. Apartial ddatation of the gullet, technically called " ingluvies." Some- 

 times it has the form of a membranous bag appended to the giillet. 

 Crustacea (Lat. crusta, a crust). A class of Articulate animals, comprising 



Grabs, Lobsters, &c., characterised by having a hard shell or cnist, which 



they cast periodically. 

 Ctenoid (Gr. kteis, a comb ; eidos, form). Applied to those scales of fishes, 



the hinder margins of which are fringed with spines or cut into comb-like 



projections. 

 Ctesophoea (Gr. Uels, a comb ; phcro, I carry). An order of Aclmozoa, 



