GLOSSARY 



687 



Cleav'age (A.S. cleofan, to cut). Divisions 

 of the fertilized egg. 



Clo-a'ca (L. cloaca, sewer). A common re- 

 ceptacle for digestive and excretory 

 wastes and the reproductive cells of 

 lower vertebrates. 



Clone (Gr. klon, twig). A group of animals 

 produced by asexual reproduction from 

 a single individual. 



Co-ag'u-la"tion (L. cogere, to drive to- 

 gether). A process of changing a sol 

 into a gel. 



Co-coon' (Fr. cocon, shell). A protective 

 covering for eggs, larvae, pupae, or 

 adult animals. 



Coe'Iom (Gr. koihis, hollow). The body 

 cavity lined with tissue of mesodermal 

 origin in which the digestive and other 

 organs lie. 



Col'Ioid (Gr. koUa, glue; eidos, form). A 

 system in which particles larger than 

 molecules of one substance are sus- 

 pended throughout a second sub- 

 stance. 



Co'lon (Gr. kolon, the colon). The part of 

 the large intestine which extends from 

 the caecum to the rectum. 



Com-men'sal-ism ( L. cum, together; mensa, 

 table). The intimate association of 

 two species in which one is benefited 

 and the other is neither helped nor 

 harmed. 



Con'ju-ga"tion (L. cum, together; jugare, 

 to join, marry). A sexual process in 

 unicellular organisms where two indi- 

 viduals unite temporarily and exchange 

 their nuclear material, later dividing. 



Con-trac'tile vac'u-ole (L. cum, together; 

 trahere, to draw; vacuus, empty). A 

 space in the cytoplasm of certain spe- 

 cies of Protozoa where fluids collect 

 before being periodically discharged 

 to the outside. 



Cop''u-la"tion ( L. copulare, to couple ) . The 

 union of two individuals in which sper- 

 matozoa are transferred from the male 

 to female. 



Cor'ne-a ( L. cornu, horn ) . The transparent 



outer covering of the anterior part of 

 the eye. 



Cor'pus (L. corpus, body). A body. 



Cor'tex ( L. cortex, bark ) . The outer layer. 



Cra'ni-um (Gr. kranion, the head). The 

 portion of the skull which envelops 

 the brain. 



Cross'ing o'ver. The process in which ho- 

 mologous chromosomes break and ex- 

 change corresponding parts. 



Cu-ta'ne-ous (L. cutis, the skin). Pertain- 

 ing to the skin. 



Cyst (Gr. kijstis, a bladder). The stage of 

 an organism, where it is encased in a 

 resistant wall. 



Cy-tol'o-gy (Gr. kytos, hollow; logos, dis- 

 course). The science that deals with 

 cell structure. 



Cy'to-plasm (Gr. kytos, hollow; plasma, 

 something molded). The protoplasm 

 of a cell, exclusive of the nucleus. 



Dac'tyl (Gr. daktylos, finger). Pertaining 

 to the finger. 



De-am'i-na"tion ( L. de, from; amino, amino 

 group). The process by which the 

 amino group is removed from the 

 amino acid. 



Def-e-ca'tion (L. de, from; faecis, dregs). 

 The evacuation of the bowels. 



De'glu-ti"tion (L. de, down; glutire, to 

 swallow). The act of swallowing. 



Den'drite ( Gr. dendron, tree ) . The branch- 

 ing protoplasmic outgrowth of a nerve 

 cell. 



Der'mal (Gr. derma, skin). Pertaining to 

 the skin, especially the deeper layers. 



Der'mis ( Gr. derma, skin ) . The inner layer 

 of the skin. 



Di-al'y-sis (L. dialysis, separation). The 

 process by which crystalloids and col- 

 loids are separated in solution. This 

 involves a natural or artificial mem- 

 brane through which unequal diffusion 

 takes place. 



Di'a-phragm (Gr. diaphragma, midriff). 

 The internal muscular layer found be- 



