GLOSSARY 907 



Cell theory (sel the'ori), the theory that all living things are composed of 



cells. 

 Centimeter (sen'ti nie'ter), one-hundredth of a meter and the equivalent of 



0.393 inches; or 1 inch equals 2..5-i centimeters. 

 Central nervous system (sen'tral), that portion of the nervous system composed 



of the brain and the spinal cord. 

 Centriole (sen'triol), a small granule within the central part of the aster in 



the mitotic figure; also known as centrosome. 

 Centrolecithal (sen'trO les i thai), refers to the tj-pe of egg with the yolk mass 



in the center, as the egg in insects. 

 Centrosome (sen'tro som), usually considered synonymous to centriole. 

 Cephalic (sefal'ik), pertaining to the head. 

 Cephalothorax (sef'alo tho'raks), a fusion of the head and thorax or chest, 



as in crayfish. 

 Cerebellum (ser ebel'liim), the large lobe of the hind brain, in front of and 



above the medulla. 

 Cerebrum (ser'ebrum), the anterior division of the brain. 

 Cercaria (surka'ria), a tailed larval stage of the liver fluke. 

 Ctenoid scale (te'noid), a type of fish scale with spines at the free margin. 

 Cervical (sur'vikal), has reference to the neck region. 

 Chaeta (ke'ta), one of the bristlelike structures in the body wall of many 



annelids, used as organs of locomotion. 

 Chelicera (kelis'era), an anterior pair of appendages in arachnids. 

 Cheliped (ke'liped), most anterior thoracic leg of cra^-fish; large pincher. 

 Chemotropism (kcmot'ropiz'm), response of an organism to chemical changes. 

 Chlorophyll (klo'rofil), the green coloring matter in plants and a few ani- 

 mals which is active in photosj'nthesis. 

 Chromosomes (kro'mo somz), bodies formed in the nucleus during mitosis which 



constitute the physical basis of inheritance. 

 Chitin (ki'tin), the hard material composing the 'exoskeleton or shell of 



Crustacea, insects, and others. 

 Chloragogue cells (klo'ragog), compose the outer layer of the intestine of 



the earthworm. 

 Chondi-in (kon'drin), the material of which cartilage is composed. 

 Chorion (ko'rion), the outer embryonic membrane of mammals. 

 Chorioid (ko'rioid), middle or vascular coat of vertebrate eyeball. 

 Chromatin (kro'matin), dark-staining substance of the nucleus of the cell. 

 Chromatophore (krd'ma to for), a colored pigment cell. 

 Chromidia (kromid'ia), scattered chromatin granules through the cytoplasm 



of some cells. . 



Chromonemata (kro mo nem' a ta), threads of chromatin distinguishable within 



chromosomes during mitosis; seen in the resting phase of some._ 

 Chyme (kim), partially digested food material which is in semiliquid con- 

 dition. 

 Cilia (sil'ia), hairlike cytoplasmic processes, used by certain protozoans for 



locomotion. 

 Cirrus (sir'iis), a bristlelike appendage. 

 Cleavage (klev'ij), the cell divisions changing the zygote into an organism 



of many cells. 

 Clitellum (klitel'um), a broadened area in the earthworm about one-third of 



the length of the body back from the head. It is glandular and serves 



in producing the cocoon. 

 Cloaca (kloa'ka), the common chamber into which the intestine, and urinary 



and genital canals discharge in some forms. 

 Cnidoblast (ni'do blast), the type of cell of the coelenterate in which the sting 



cell or nematocyst develops. 



