GLOSSARY OF EMBRYOLOGICAL TERMS 275 



Egg, Giant — abnormal polyploid condition where chromosome complexes 

 are multiplied, resulting in giant cells and embryos. 



Egg, Homolecithal — egg (e.g., mammal) in which but little yolk is scat- 

 tered throughout cytoplasm. 



Egg, Isolecithal — eggs with homogeneous distribution of yolk; may be iso- 

 lecithal, alecithal, or homolecithal. 



Egg Jelly — mucin covering deposited on amphibian egg as it passes 

 through oviduct. 



Egg, Macrolecithal — egg with large amount of yolk, generally telolecithal. 



Egg Membranes — include all egg coverings such as vitelline membrane, 

 chorion, and tertiary membranes. 



Egg, Microlecithal — egg with small amount of yolk. (Syn., meiolecithal 

 egg, oligolecithal egg.) 



Egg Receptor — part of Lillie's scheme picturing parts that go into the 

 fertilization reaction involving fertilizin. Egg receptor plus ambo- 

 ceptor plus sperm receptor gives fertilization. 



Egg, Telolecithal — egg with large amount of yolk concentrated at one pole. 



Egg Water — watery extract of materials diffusing from living eggs, pre- 

 sumably the "fertilizin" of Lillie. (Syn., egg water extract.) 



Ejaculation — forcible emission of mature spermatozoa from body of male. 



Ejaculatory Duct — short portion of mesonephric duct (mammal) between 

 seminal vesicles and urethra. 



Emboitement — preformationist theory of Bonnet and others based on 

 idea that ovary of first female (Eve?) contained the miniatures of all 

 subsequently existing human beings. (Syn., encasement theory.) 



Embryo — any stage in ontogeny of fertilized egg, generally limited to pe- 

 riod prior to independent food-getting. Stage between second week 

 and second month of human embryo. 



Endocardium — delicate endothelial tissue forming lining of heart. 



Endochondral Bone — bone preformed in cartilage. (Syn., cartilage bone.) 



Endoderm — innermost layer of didermic gastmla. (Syn., entoderm.) 



Endolymphatic Duct — See Ductus Endolymphaticus. 



Endolymphatic Sac — See Saccus Endolymphaticus. 



Endoplasm — inner medullary substance of (egg) cell which is generally 

 granular, soft, watery, and less refractive than ectoplasm. 



