U62 GLOSSARY 



EGG, ECTOLECITHAL - egg having the formative protoplasm surrounded by yolk. 



EGG ENVELOPE - material enveloping the egg but not necessarily a part of the egg, generally derived from the 

 ovary (vitelline membrane or chorion of fish) or from the oviducts (Jelly or albumen). 



BtXJ, GIANT - abnormal polyploid condition where chromosome complexes are multiplied, resulting In giant 

 cells and embryos. 



EGG, HOMOLECITHAL - egg which has little yolk scattered evenly throughout the cytoplasm (e.g., sea urchin, 

 mammal). Syn., Isoleclthal egg and obsolete term, aleclthal egg. 



EGG JELLY - the mucin covering deposited on the amphibian egg as It passes through the oviduct. 



EGG, MACEOLECITHAL - egg with large amount of yolk, generally teloleclthal. 



EGG MEMBRANES - Includes all egg coverings such as vitelline membrane, chorion, and the tertiary coverings 

 from the oviduct. 



EGG, MICROLECITHAL - egg with small amount of yolk. Syn., meloleclthal, ollgoleclthal. 



EGG RECEPTOR - part of Llllle'a scheme picturing parts that go Into the fertilization reaction Involving 

 fertlllzln. ifeg receptor plus amboceptor 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 (Echlnoderm) eggs, presumably the "fertlllzln" 

 of Llllle. Syn., egg water extract. 



EIDOGEN - a chemical substance possessing the power to modify an embryonic organ otherwise induced; force 

 In regional differentiation, possibly including Inductors of the second-grade level. 



EINSTECKUNG - method of testing the power of induction by implanting a tissue, living or dead, or a 

 chemical substance, into the blastocoel of a living gastrula. 



ELECTRODYNAMIC THEORY OF DETOLOPMENT - theory that cell mitoses establish a definite differential poten- 

 tial capable of orienting growing nerve roots (axis cylinders) and thereby directing them (e.g., to- 

 ward the brain) . 



EMANCIPATION - dynamic segregation from "autonomisatlon" (Weiss, 1935); establishment of local autonony 

 within embryonic areas. 



IMBRYO - a stage in. the ontogeny of the fertilized egg limited to the period before the Intake of food. 



EMBRYOMA - (See teratoma) 



EMBRYONIC FIELD - region of formative processes within the embryo, larger th£m the area of ultimate 

 realization of structures concerned (Gurwitsch, 1922). 



EMBRYONIC SHIELD - a thickened, shield-like region of the blastoderm which will give rise to the body of 

 the (fish) embryo. 



EMBBYOTHOPHY - the means or the actual nourishment of the embryo. 



ENCAPSIS - superordinate system within the embryo. Processes may be purposeful for a subordinate system 

 and yet destroy another system to which it itself Is subordinate. These relations are called 

 encapsla ( Heidenhain) . 



ENCHYLEMA - the liquid phase of the endoplasm in which are suspended yolk granules and mitochondria 

 (Monne) . 



ENDODEHM - the Innermost layer of the dldermlc gastrula. Arises from the vegetal hemisphere of amphibia. 

 Syn., entoderm. 



ENDODERMISATION - shifting of an animal-vegetal gradient of an egg toward the vegetal gradient, causing 

 hyper-development of the endodermal structures. Can be brought about by physical, chemical, or 

 surgical means. 



ENDOPLASM - Inner medullary substance of the egg cell which Is generally granular, soft, watery, and less 

 refractory than the ectoplasm. Surrounded by ectoplasm. 



ENDYSIS - the development of a new cuticular covering, opposed to ecdysis. 



ENTELECHY - Driesch's theory of harmonious, equlpotentlal system suggested an agent controlling develop- 

 ment which he termed "elan vital". An Intensive manifoldnesa; the intangible controlling order of 

 developnent ("Intensive Mannigfaltigkelt" of Driesch). 



ENTOMESOBLAST - cell which will give rise to the trunk mesoderm in the determinate type of cleavage 

 characteristic of annelids. 



ENTO-MESODESM - refers to that portion of the invaglnatlng blastoporal lips which will induce the forma- 

 tion of medullary fields in the amphibia. 



ENTOPIC - in the normal position, opposed to ectopic (referring to transplsints) . 



ENTRANCE CONE - the ten^oraiy depression on the surface of the egg following the entrance of the 

 spermatozoon. 



ENTRANCE PATH - (See path, entrance or penetration) 



ENTWICKLUNGSMECHAHIK - causal embryology (Roux); the seat and effective duration of the morphogenetic 



forces which are explored, by microsurgical means, and which seem to be responsible for the develop- 

 ment of embryonic .segregation (Lehmann, 19'+2). 



ENTWICKLUNGSPOTENZEN - the total accomplishment of a blastema, experimentally determined (Raven). 



EPIBOLY - growing, spreading, or flowing over; surrounding of inner masses (yolk and/or cells) by over- 

 growing ectoderm; process by which the rapidly dividing animal pole cells (often mlcromeres) grow 

 over and enclose the vegetal hemisphere material. Increase in areal extent of the ectoderm. 

 (Simile: rubber cbp being pulled down over grapefruit.) 



EPIGAMIC - tending to attract the opposite sex. 



EPIGENESIS - developing of systems starting with primitive, homogeneous, lowly organized condition and 

 achieving great diversification. Term coined by Harvey, the eLntlthesis of preformation. 



EPIGNATHUS - union upon the Jaw of parasitic growth. 



EPIMOEPHOSIS - proliferation of material precedes the development of new parts. 



ERGASTOPLASM - basophilic parts of the cytoplasm, mitochondria of cytologlats. 



