234 GLOSSARY 



Endopodite: the innermost of the two terminal branches of the typical 



crustacean leg. 

 Endoskeleton: an internal supporting structure. 

 Endostyle: a ciliated and glandular groove in the midventral Hne of the 



pharynx in ascidians. 

 Entoderm: the innermost layer of cells in the Porifera and Coelenterata. 

 Entosarc : the inner granular protoplasm in protozoans. 

 Epicranium: the sclerite forming the dorsal, median, and lateral walls of 



the head in insects. 

 Epigynum: a cuticular plate covering or accompanying the female genital 



pore in many species of spiders. 

 Epiphragma: the disk of calcified slime with which a land snail can close 



the opening of its shell. 

 Epipodite: a membranous projection of the protopodite in crustaceans. 

 Excretion; the ehmination of nitrogenous wastes from the body. 

 Excurrent: passing outward. 

 Exopodite: the outermost of the two terminal branches of the typical 



crustacean leg. 

 Extensor muscle : a muscle that extends an organ. 

 Extremity: a paired lateral or ventral appendage of the body of an animal, 



used primarily for locomotion, although in many cases having second- 

 arily some other function. 

 Exumbrella: the aboral side of a medusa. 



Femur: a segment of an insect's or a spider's leg; the thigh bone in ver- 

 tebrates. 



Fertilization: the union of the spermatozoon and the ovum. 



Flagellum: a vibratory threadlike projection of certain cells. 



Flame cell: the terminal cell of an excretory tubule of flatworms. 



Flexor muscle: a muscle that bends an organ. 



Food vacuole : a globule of water containing food particles. 



Front: the anterior median portion of the epicranium. 



Funiculus: a mesenteric strand connecting the stomach pouch with the 

 body wall in bryozoans. 



Funnel : the siphon of a cephalopod. 



Ganglion: an aggregation of nerve cells. 



Gastrolith: a calcareous body sometimes present in the stomach of crusta- 

 ceans. 



Gastrovascular space: the central cavity in Coelenterata. 



Gastrula: a stage in the development of the embryo in which two cell 

 layers only are present, the ectoderm and the entoderm. 



Gena: the lateral portion of the epicranium in insects. 



Genital plate: a sclerite at the posterior end of the abdomen in the male 

 grasshopper. 



