Genuine Pleiotroplsm — 63 — Gonadotrophin 



Gestation. — Pregnancy; the carrying of the foetus in the 

 uterus; the period during which the foetus is carried in the 

 uterus. 



Gestation Periods. — Averages, in days: 



Gigantism. — Appearance of giant forms (often polyploid). 



Glandular Hermaphroditism. — The presence in the one 

 gonad of both ovarian and testicular material. 



Gliding Intergradation. — Continuous variation. 



Gloger's Rule. — The melanins increase in the warm and 

 humid parts of the range. Reddish or yellowish-brown phaeo- 

 melanins prevail in arid climates where the blackish eumelanins 

 are reduced. The phaeomelanins are subject to reduction in 

 cold climate, and in extreme cases also the eumelanins (polar 

 white) (Mayr, 1942). 



Golgi Apparatus. — A mechanism, found almost exclusively 

 in animal cells, which moves about in the immediate vicinity of 

 the nucleus and consists either of minute structures, called 

 Golgi bodies, or a single reticulate mechanism. 



Golgi Nets. — A part of the Golgi element. 



Gonad. — An organ within which ova or spermatozoa are 

 formed. 



Gonadectomy. — Excision of gonads. 



Gonadotrophic, Gonadotropic Hormones. — Any hormones 

 which stimulate the gonad. 



Gonadotrophin. — A general term for any gonadotrophic hor- 

 mone, i.e. a hormone which stimulates the gonads. Gonado- 

 trophin (A. P.) is a preparation made from anterior pituitaries, 



