GLOSSARY 



epigenesis, epijen'esis (Gr. epi, upon; genesis"), a theory of development 



(see p. 272). 

 epipodite, epip'o dlt (Gr. epi, upon; pous, foot), a process developed upon 



the basal joint of some of the appendages of certain crustaceans. 

 epithelium, epithelium (Gr. epi, upon; thallo, I grow), the layer of cells 



forming the surface of all the internal membranes of the body. 

 evolution, evo lu'shon (L. e, out; volvo, roll), a theory of development (see 



p. 291). 

 excretion, ekskre'shon (L. ex, out; cretus, separated), the elimination of 



useless or harmful substances from the body. 

 exopodite, tksop'odlt (Gr. exo, outside; pous, foot), the outer of the two 



main divisions of a typical crustacean appendage. 

 exoskeleton, ek so skel' e ton (Gr. exo, outside; skeleton}, any structure pro- 



duced by the hardening of the integument. 



s (L.ftzx, dregs), undigested particles cast out by an animal. 

 family, fa m'ili (L. familia, a household), the name of a group above a 



genus and below an order. 

 fauna, fd'na (L. Faunus, one of the gods of the fields), all the animals pe- 



culiar to a country, area, or period. 

 ferment, fer'ment ( L. fermentum, leaven), a substance which transforms an 



organic substance into new compounds. 

 fertilization, fl-r'ti li za'shon (L. fertilis, fruitful), the union of a sperma- 



tozoon with an egg. 

 flagellum, flajel'um (L. flagellum, a whip), the whiplike appendage of 



many Protozoa. 



foliaceous, fo li d'shius (L,. folium, leaf) resembling a leaf. 

 function, fungk'shon (L. functio, performance), the mode of action proper 



to an organ or structure. 



gamete, gam'cf (Gr. gamete, a wife), a reproductive cell which unites with 



another reproductive cell to form a zygote. 

 ganglion, gang'gli on (Gr. gangglion, a tumor under the skin near a tendon), 



a mass of nervous tissue containing nerve cells and giving rise to nerve 



fibers. 



gastric, gas'trik (Gr. gaster, stomach), of or pertaining to the stomach. 

 gastrolith, gas'tro lith (Gr. gaster, stomach ; lithos, stone), a stony concre- 



tion in the stomach of certain crustaceans. 

 gastrula, gas'tro la (dim. of Gr. gaster, stomach), an embryo consisting of 



two germ layers inclosing a central cavity. 

 genital, jen'ital (L. genitalis, serving to beget), pertaining to the organs of 



generation. 



