668 



COLLEGE ZOOLOGY 



and birds and may also appear in embryonic 

 stages of mammals. Also found in some in- 

 vertebrates, as in many insects. 



Clone (Gr. klon, twig). The offspring pro- 

 duced by asexual reproduction of a single 

 animal. 



Cni'do-blast (Gr. knide, nettle; blastos, bud). 

 A type of cell in which the nematocyst is 

 found. 



Cni'do-cil (Gr. knide, nettle; L. cilium, eye- 

 lid). A hairlike process projecting from the 

 outer margin of the cnidoblast. 



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

 tive case about a mass of eggs, a larva, a 

 pupa, or an adult animal. 



Coe'lom (Gr. koilis, hollow). A body cavit)' 

 lined with tissue of mesodermal origin. 



Coe'no-sarc (Gr. koinos, common; sarx, flesh). 

 The inner, cellular part of a hydroid as dis- 

 tinguished from the outer surrounding 

 perisarc. 



Co-en'zyme (L. cum, with; Gr. en zume, 

 leaven ) . A substance associated with and ac- 

 tivating an enzyme. 



Cold'-blood'ed. Poikilothermic; without abil- 

 ity to regulate the body temperature by 

 physiologic means; commonly said of fish, 

 reptiles, and amphibians whose temperatures 

 approximate that of the environment. 



Col'loid (Gr. kolla, glue; eidos, form). A state 

 of matter in which particles larger than sin- 

 gle molecules are distributed throughout a 

 medium such as a liquid, gas, or solid and 

 which is called the dispersion medium. 



Co'lon (Gr. kolon, colon). The anterior por- 

 tion of the large intestine of a vertebrate. 



Coro-ny (L. colonia from colere, to cultivate). 

 A group of individuals, unicellular or multi- 

 cellular, of the same species, which have 

 developed from a common parent and re- 

 main organically attached or held together; 

 also used for insect societies. Opposite of 

 solitary. 



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

 table). An association of individuals of two 

 different species in which at least one is 

 benefited, and the other is neither benefited 

 nor harmed. 

 Com'mis-sure (L. cum, together; mittere, to 

 send ) . A group of connective nerve fibers 

 uniting t^vo like structures in the two sides 

 of the brain or spinal cord; or similar cords 

 connecting nerve centers elsewhere. 



Com-mu'ni-ty (L. communitas, from cojn- 

 munis, common). A more or less complex 

 group of plants or animals that occupy a 

 particular area. 



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

 join, marry). A method of reproduction in 

 which two unicellular animals unite, ex- 

 change nuclear material, and then divide, as 

 in the paramecium. 



Con'junc-ti"va (L. cum, together; jungere, to 

 join). A continuation of the mucous mem- 

 brane over the cornea of the eye, connecting 

 the cornea with the outer covering of the 

 eyelid. 



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

 trahere, to draw. L. vacuus, empty). A struc- 

 ture within the cytoplasm of certain proto- 

 zoan cells in which liquids collect before 

 they are periodically expelled to the outside. 



Co'nus ar-te'ri-o"sus (L., cone. Gr. arterio, 

 arter}'). The expanded cone-shaped struc- 

 ture of the right ventricle which empties into 

 the aorta. 



Con-ver'gence ( L. convergere, to turn ) . Mor- 

 phologic similarity in distantly related forms. 



Cop'u-la"tion (L. copulate, to couple). Sex- 

 ual union of two individuals involving the 

 transference of sperms from the male to the 

 female body. 



Cor'a-coid ( Gr. korax, crow; eidos, form ) . One 

 of the bones of the pectoral girdle of many 

 vertebrates, especially land forms in verte- 

 brates. 



Co'ri-mn (L. cerium, leather). The inner der- 

 mal portion of the skin. 



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

 transparent, layer of the eye. 



Cor'tex (L. cortex, bark). Outer portion of a 

 structure. 



Cos'tal car'ti-lage (L. costa, rib; cartilage, 

 cartilage). The cartilages that attach the ribs 

 to the sternum in a vertebrate. 



Cox-op'o-dite (L. coxa, hip; Gr. pons, foot). 

 That part of an arthropod appendage which 

 lies next to the body. 



Cra'ni-um (Gr. kranion, head). That part of 

 the vertebrate skull which encloses the brain; 

 the brain case. 



Crop (A.S. crop or crepp, top bunch). An 

 expanded portion of the anterior part of a 

 digestive tract specialized for storage. 



Cross-fer'ti-li-za"tion. The fertilization of an 

 egg produced by one individual, with a 



