GLOSSARY 53 



Calcareous: Containing calcium carbonate which may be deter- 

 mined by touching with hydrochloric acid. If the material is 

 calcareous it will effervesce. 



Carapace: The chitinous or calcareous covering of the cephalo- 

 thorax of a crustacean such as the crayfish or lobster. Also the 

 bony dorsal covering of a turtle. 



Caudal filaments: Threadhke outgrowths from the posterior end 

 of the body of an animal. 



Cephalothorax: The fused head and thorax of such an animal as the 

 crayfish. 



Chelicerae: Appendages of the spider group found immediately 

 in front of the mouth. 



Chitin: A horny substance forming the outside covering of Crus- 

 tacea, insects, and many other animals. 



Chitinized: Impregnated with chitin. 



Cilia (sing. Cilium): Minute hairlike structures occurring on the 

 surface of certain cells as in Paramecium. 



Cloaca: A common passage through which the intestines, kidneys, 

 and sexual organs discharge their products in some fishes, 

 amphibia, reptiles, birds, and lower mammals. 



Cocoon: A case in which eggs are laid and in which the larvae are 

 developed; also a silky covering around a pupa. 



Colony: Two meanings: (i) animals organically connected as 

 Plumatella; (2) animals not organically but socially con- 

 nected as a colony of bees. 



Complete metamorphosis: A term applied to the life-history of 

 certain animals, especially insects, in which the adult is wholly 

 unlike the grublike larvae in appearance. 



Conus arteriosus: A bulblike structure at the base of the aorta 

 which contains a number of valves. 



