GLOSSARY 373 



Coelenterata (se len' ter a' to). The phylum to which Hydra, the hydroids, jellyfishes, 

 and siphonophores belong. For definition see Chapter XII. 



Coelenteron (se len' ter on). A cavity in forms like Hydra which have only one body 

 cavity. It serves the digestive and circulatory functions and is therefore also 

 called the gastrovascular cavity, 



Coelom {see' lome). The true body cavity, a cavity within the mesoderm on the 

 walls of which the principal reproductive organs are located. 



Ccenosarc (se' no sark). The cellular living part of a hydroid, as distinguished from 

 the perisarc. 



Collared epithelium {koV lerd). Epithelium each of whose cells bears a collar. 



Collecting tubule {kol leki' ing tu' bule). One of a number of tubes leading across 

 the kidney of the frog from Bidder's canal to the ureter. 



Colloid (kol' hid). A mixture in which particles greater in size than molecules are 

 held in suspension in a liquid. 



Colloidal {kol hi' dal). Contained in a liquid in aggregations greater than molecules. 



Colony {koV o ni). A group of individuals of the same species organically connected 

 with each other. 



ColubridsB {ko lu' bri dee) A family of snakes. 



Colubrinae {kol' u bri' nee). A subfamily of the family Colubridse (snakes). 



Columnar epithelium {ko him' ner). Epithelium in which the cells have one dimen- 

 sion distinctly greater than the others, that dimension being vertical to the surface 

 covered by the epithelium. 



Comanchian {ko man' chi an). Pertaining to Mesozoic time prior to the Cretaceous; 

 formerly called lower Cretaceous. 



Commissure {kom' mi shure). A group of connecting nerve fibers. 



Common bile duct {kom' mon bile' dukt'). The tube leading from the liver to the 

 small intestine and serving to convey bile to the small intestine. 



Compound gland {kom pound'). A branching gland. 



Conchology {kong kol' o ji). The zoology of the MoUusca. 



Conemaugh {ko' ne maw). A rock formation of eastern United States, belonging to 



Permo-Carboniferous time. 

 Coniferous {ko nif er us). Cone-bearing (as pine or cypress trees). 



Conjugation {kon' ju ga' shun) . The meeting of two cells for exchange of nuclear 

 material or (by extension of meaning) for complete fusion. 



Coimective tissue {kon nek' tiv fish' u). A tissue composed of cells and certain other 

 material produced by the cells, which in its simple form binds organs and other 

 tissues together. In a broader sense it includes such modified tissues as cartilage, 

 bone, tendon and ligaments. 



Contractile tissue {kon Irak' til tish' u). Any tissue capable of active contraction; as 

 muscle. 



Contractile vacuole {kon trak' til vak' u ole). A vacuole whose contents are periodic- 

 ally ejected to the outside of the cell in which it is contained. 



Copepod {ko' pe pod). Any one of a group of small Crustacea. 



Copulation {kop' u h' shun). The act of introducing spermatozoa into the body of 

 the female. 



Coracoid (A or' a hoid). A bone of the ventral part of the pectoral girdle of vertebrate 

 animals; a distinct bone in the bony fishes, amphibia, reptiles, birds and lowest 

 mammals, but fused with the scapula in the higher mammals. 



