98 ZOOLOGY DIEECTIONS 



Cephalothorax — A term applied to the anterior part of the body 

 of an animal in which head and thorax are not separated 

 from one another. 



Chela — The large claw of a crustacean. 



Cheliped — The crustacean leg bearing the chela or large pincher. 



Cleavage — The division of a cell following the division of the 

 nucleus. 



Cloaca — The posterior region of an alimentary canal that holds 

 the waste from the digestive and excretory organs. 



Coelenteric cavity — The single cavity of the body of a coelente- 

 rate which at the same time serves as body cavity and di- 

 gestive cavity. 



Conjugation — The fusion of two protozoans for an exchange of 

 cytoplasm or of nuclear material. 



Cuticula — A thin, non-cellular body covering of many inverte- 

 brates. 



Differentiation— The specialization of a group of cells for a 

 definite, restricted function. 



Dorsal—' ' The back ; " or more strictly the part of the body di- 

 rected away from the surface upon which the animal nor- 

 mally rests. 



Elytra^The horny outer wings of the Coleoptera. 



Epipodite — In the crayfish, a membranous projection from the 

 protopodite extending into the gill chamber. 



Fertilization— The fusion of two gametes to form a single cell, 

 the zygote. 



Fission — A method of asexual reproduction in which the body 

 of an individual becomes split into two equal parts. 



Gastrula— That stage in the development of a new individual 



