1+66 GLOSSARY 



GECMTH - cell proliferation; a developmental (synthetic) Increase In total mass of protoplasm at the expense 



of raw materials; an embryonic process generally following differentiation (see heterogony) . 

 GBOWTH, ACCRBTIONABY - growth Involving Increase In non-living structural matter. 

 GBOWTH, AUXETIC - growth Involving Increase In cell size alone. 



GBOWTH CIECUMSTAMTIAIS - factors not responsible for the characteristics but for the realization of growth. 

 GBOWTH COEFFICIENT - growth rate of a part relative to the growth rate of the whole (organism) depending 



on factors Inherent In the tissues concerned (see heterogonlc growth). 

 GBCWTH, DiTSHAEMOBIC - heterogonlc growth to an extreme, relative growth rates becone extremely unbalanced 



(Champy, I92U). 

 GROWTH EQUILIBErUM - regulation of growth of part In respect to the organism as a whole. 

 GBCWTH GRADIENT - quantitative grading of growth variables In such a way that the body appears to be a 



field system of Interconnected metabolic areas. 

 GROWTH, HETEROGONIC - different rates of growth In different regions of the embryo, or In transplant as 



compared with host control organ. (See heterauxesls. ) 

 GBCWTH, ISOGONIC - similar rates of growth In different regions of the embryo. 

 GBCWTH, MOLTIPLICATIVE - growth involving Increase In the number of nuclei and of cells. Syn. , merlstlc 



growth. 

 GBCWTH, PARTITION COEFFICIENTS OF - inherent growth rates (e.g., in limb rudiments) involving changes In 



proportions. 

 GBOWTH POTENTIALS - capabilities or predispositions for growth. 

 GBCWTH REGULATION - a substance (R) postulated by Harrison, distinct from nutritional factors, present 



In the circulating medium of the organism, which controls growth. 

 GUANOPHORES - pigmented cells found in lateral line organs and in pericardium, having yellow guanln 



crystals which give a highly refractive metallic luster to the cells. 

 GYNAWDRCWORPH - condition where part of an animal may be male and another part female, not to be confused 



with hermaphroditism which is concerned primarily with the gonads. 

 GYNOGAMONES - highly acidic, polysaccharide, containing protein of low nitrogen content, and elongate, 



gel-forming molecular structure. Possibly the fertlllzlns of Lillle, but so naned by Hartmann. 

 GYNOGENESIS - development of an egg with the egg nucleus alone. This may be brought about by rendering 



the sperm nucleus functionless for syngany by irradiation or other neans, or by surgical removal. 



Opposed to androgenesis. 



HAEMOTROPHE - the nutritive substances supplied to the embryo from the maternal blood stream of vivi- 

 parous animals. 



HAPLOID - having a single complete set of chromosomes, none of which appear in pairs, the condition in 

 the gametic nucleus. Opposed to diploid, or twice the haplold, where the chromosomes appear as 

 pairs (e.g., as in somatic cells). 



HARMONIOUS-EQUIParENTIAL SYSTEM - an embryonic system in which all parts are equally ready to respond 

 to the (organism as a) whole. The segmenting egg is a system of equivalent parts subdividing 

 harmoniously, according to inherent tendencies, Into smaller systems until the proper role in 

 development has been assigned to each part of the embryo (Driesch). Isolated blastomeres tend to 

 give congjlete but smaller embryos. 



HARRISON'S RULE OF MINOR SYMMETRY - 



(1) If the antero-posterior axis of a limb-bud Is reversed in a graft, the resulting limb will 

 have the asymmetry proper to the opposite side of the body from that on which it is placed 

 (I.e., it becomes dlsharmonlc, whether originally taken from the same or the opposite side). 



(2) If the antero-posterior axis is not reversed in grafting, the resulting limb will have the 

 asymmetry proper to the side on which It is placed (i.e., it becomes dlsharmonlc, whether 

 originally taken from the same or the opposite side). 



(5) If double limbs arise, the original member (I.e., the first to begin development) will have 

 Its asymmetry fixed with rule (1) or (2) depending upon the orientation of the graft, while 

 the secondary member will be che mirror Image of the first. 



HATCHING - the beginning of the larval life of the amphibian, accomplished by temporarily secreted 



hatching enzymes which aid the embryo to escape its gelatinous capsule; the process of emergence of 

 the chick embiyo from its shell, involving critical changes In structure and functions. 



HEDONIC - reptilian skin glands which secrete musk and are active during the breeding season. 



HEMIBLASTULA - half-blastula derived by cauterizing one blastonere of the 2-cell stage (Boux). 



HSWIGONY - one-half egg fragment (Delage, I899). 



HQUKAHYOTIC - haplold. In merogony, hemikaryotic arrhenokaryotlc androgenetlc or in artificial par- 

 thenogenesis, hemikaryotic thelykaryotl c gynogenetlc. 



HEMIMEUJS - failure of distal portion of appendages to develop. 



HENSEN'S NODE - einterior end of the primitive streak of the chick embryo, corresponding to the region 

 of the dorsEil lip of the amphibian egg; region of future midbrain (position). 



HENSEN'S THEOBY - nerve fibers are formed out of protoplasmic bridges which exist throughout the embryonic 

 body, protoplasmic bridge theory. 



HEBMAPHBODITE - an Individual capable of producing both spermatozoa and ova. 



HEBTWIG'S LAW - the nucleus tends to place itself In the center of its sphere of activity; the longitudinal 

 axis of the mitotic spindle tends to lie in the longitudinal axis of the yolk-free cytoplasm of the 

 cell. 



