Knight — 48 — Dictionary 



Ecospecies, Ecotype. — A distinct race resulting from the 

 selective action of a particular environment. More strictly 

 "ecotype" is "used as an ecological sub-unit to cover the product 

 arising as a result of the genotypical response of an eco- 

 species to a particular habitat" and "ecospecies" is "the genotype 

 compound narrowed down to the ecological combination- 

 limit" (Turesson). 



Ecotopic Adaptation. — Adaptation to the detailed features 

 of a particular type of habitat within a region (Huxley). 



Ecotype. — See under Ecospecies. 



Ectogenesis. — The artificial development of an embryo by 

 culture in vitro. 



Ectogeny. — Metaxenia; the physiological effect of pollen 

 on the maternal tissues. 



Ectopic Gestation. — Extra-uterine growth of the foetus; 

 eccyesis. 



Ectoplasm. — Non-granular, peripheral cytoplasm ; exoplasm. 



Ectoplast. — Ectoplasm, q.v. 



Ectosarc. — Ectoplasm, q.v. 



Ectosomes. — Specific cytoplasmic granules characteristic of 

 the primordial germ-cells and stem-cells in copepods. A form 

 of 'germ-cell determinant' (Haecker; Wilson). 



Ectosphere. — The peripheral region of the centrosphere. 



Egg. — The female gamete in animals; ovum. 



Ejaculatory Ducts. — Small slit-like openings in the floor of 

 the urethra, through which the spermatozoa pass from the 

 vasa deferentia during ejaculation. 



Elaioplast. — An oil-producing plastid. 



Electosomes. — A general term applied to chondriosomes 

 (mitochondria) considered as centres of specific chemical ac- 

 tion (Regaud; Wilson). 



Emasculation. — (i) The removal of the anthers from a bud 

 or flower, (ii) Castration. 



Emasculatome. — An instrument, generally consisting of 

 double-hinged pincers, used in emasculation for crushing the 

 spermatic cord. 



Emboitement. — Encasement, q.v. 



Embryo, — The non-self-supporting immature organism formed 

 from the zygote by segmentation and differentiation. 



Embryo-cell. — One of two cells formed from first division 

 of fertilized egg in certain plants, developing later into em- 

 bryoj the other developing into suspensor (Henderson). 



