590 GLOSSARY 



chaet (ket). G.; bristle. Chaeta (ke' ta). A bristle set in the body wall and form- 

 ing the locomotor organ in many annelids. 

 character. A heritable and visible characteristic in an animal connected with the 



presence or absence of a gene, or the interaction of two or more genes. 

 chelicera (ke lis' er a). One of the anterior pair of appendages of an arachnid, 

 cheliped (ke' 11 p6d). The first walking leg of a crayfish. 



chemotropism (ke m6t' ro piz'm). The response by an organism to chemical stimu- 

 lation; adj., chemotropic (kgm 6 tr6p' ik). 

 Child, Charles M. American zoologist, at University of Chicago; 1869- . 

 chitin (ki' tin) . A substance that gives hardness to the cuticula of many invertebrates, 

 chlorophyll (klo' ro fll). The green coloring matter contained in the chloroplasts of 



cells and carrying on photosynthesis. 

 chondrin (kon' drin). The substance which forms cartilage. 

 chord (kord). G.; a string. 

 chordate (kor' dat). An animal belonging to the phylum Chordata and possessing a 



notochord at some time during its life. 

 chorion (ko' ri 6n). The outer embryonic membrane of land vertebrates; the same 



name is also applied to the shells of insect eggs; adj., chorionic (ko rl 6n' jQc). 

 choroid (ko' roid). The vascular middle coat of the vertebrate eye; adj., choroidal 



(ko roi' dal). 

 chromatin (kro' ma tin). The deeply staining substance in the nucleus of cells; adj., 



chromatic (kr6 mSt' Ik). 

 chromatophore (kro' ma to for). A cell containing pigment. 

 chromidia (kro mtd' I a). Masses of chromatin scattered through the cytoplasm of a 



protozoan cell which represent a "distributed" nucleus. 

 chromomere (kr5' mo mer). An individual chromatin granule in a chromosome. 

 chromosome (kro' mo som). A characteristic mass of chromatin developed from 



the chromatin network in a nucleus during mitosis; adj., chromosomal 



(kro mo so' mil). 

 chyle (kll). That part of the food, consisting largely of emulsified fats, which is 



absorbed through the walls of the small intestine and collected by the lymphatic 



vessels. 

 chyme (kim). Food reduced to liquid form. 

 cUium (sir I um). One of many minute, hairlike, vibratile structures on the surface 



of a cell; also the eyelashes; adj. ciliary, referring to either of the above or to many 



structures in the vertebrate eye. 

 cirrus (sir' rtis). A slender, usually flexible, and often branched appendage having 



one of many functions, such as copulation in trematodes and mollusks, respiration 



in some annelids, and touch in many animals; also one of the legs of barnacles, 

 cleavage. The division of the egg cell and of the blastomeres in the early stages of 



embryogeny. 

 Cleveland, Lemuel R. American parasitologist, at Harvard Medical School; 1892- . 

 cloaca (klo a' ka). A common passageway to the outside of the body for the digestive, 



excretory, and reproductive systems; adj., cloacal. 

 cnidoblast (ni' do blast). A cell in a coelenterate in which develops a nematocyst. 

 cocoon (ko koon'). A protective covering for a larva, a pupa, a mass of eggs, or even 



one formed about an adult animal. 

 coel (sel). G.; a hollow chamber. 

 coelom (se' 16m). A body cavity inclosed by mesoderm; in embryogeny the gonads 



arise from its wall and into it the inner ends of the excretory ducts open; adj., 



coelomic (se 16m' Ik). 

 colloid (k6r oid). A substance of gluelike or jelly-like consistency which in solution, 



or suspension, will not pass through an organic membrane; adj., colloidal 



(k6 loi' dal). 



