GLOSSARY 



481 



GROWTH - cell proliferation; a developmental 

 (synthetic) increase in total mass of proto- 

 plasm at the expense of raw materials; an 

 embryonic process generally following dif- 

 ferentiation (see heterogony). 



GROWTH, ACCRETIONARY - growth involving 

 increase in non-living structural matter. 



GROWTH, AUXETIC - growth involving increase 

 in cell size alone. 



GROWTH CIRCUMSTANTIALS - factors not 



responsible for the characteristics but for 

 the realization of growth. 



GROWTH COEFFICIENT - growth rate of a part 

 relative to the growth rate of the whole 

 (organism) depending on factors inherent in 

 the tissues concerned (see heterogonic 

 growth). 



GROWTH, DYSHARMONIC - heterogonic growth 

 to an extreme, relative growth rates be- 

 come extremely unbalanced (Champy, 1924). 



GROWTH EQUILIBRIUM - regulation of growth 



of part in respect to the organism as a whole. 

 -GROWTH GRADIENT - quantitative grading of 



growth variables in such a way that the body 

 appears to be a field system of intercon- 

 nected metabolic areas. 



GROWTH, HETEROGONIC - different rates of 

 growth in different regions of the embryo, 

 or in transplant as compared with host con- 

 trol organ. (See heterauxesis. ) 



GROWTH, ISOGONIC - similar rates of growth 

 in different regions of the embryo. 



GROWTH, MULTIPLICATIVE - growth involving 

 increase in the number of nuclei and of cells. 

 Syn. , meristic growth. 



GROWTH, PARTITION COEFFICIENTS OF - 

 inherent growth rates (e. g. , in limb rudi- 

 ments) involving changes in proportions. 



GROWTH POTENTIALS - capabilities or pre- 

 dispositions for growth. 



GROWTH REGULATION - a substance (R) pos- 

 tulated by Harrison, distinct from nutri- 

 tional 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 guanin crystals which give a 

 highly refractive metallic luster to the cells. 



GYNANDROMORPH - condition where part of an 

 animal may be male and another part fe- 

 male, not to be confused with hermaphro- 

 ditism which is concerned primarily with 

 the gonads. 



GYNOGAMONES - highly acidic, polysaccharide, 

 containing protein of low nitrogen content, 

 and elongate, gel-forming molecular struc- 

 ture. Possibly the fertilizins of Lillie, but 

 so named by Hartmann. 



GYNOGENESIS - development of an egg with the 

 egg nucleus alone. This may be brought 

 about by rendering the sperm nucleus func- 



tionless for syngamy by irradiation or other 

 means, or by surgical removal. Opposed 

 to androgenesis. 



HAEMOTROPHE - the nutritive substances sup- 

 plied to the embryo from the maternal blood 

 stream of viviparous 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 haploid, 

 where the chromosomes appear as pairs 

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



HARMONIOUS-EQUIPOTENTIAL SYSTEM - an 

 embryonic system in which all parts are 

 equally ready to respond to the (organism 

 as a) whole. The segmenting egg is a sys- 

 tem of equivalent parts subdividing harmon- 

 iously, 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 complete 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 result- 

 ing limb will have the asymmetry 

 proper to the opposite side of the body 

 from that on which it is placed (i. e. , 

 it becomes disharmonic, whether or- 

 iginally taken from the sanne or the 

 opposite side). 



(2) If the antero-posterior axis is not re- 

 versed in grafting, the resulting limb 

 will have the asymmetry proper to the 

 side on which it is placed (i. e. , it be- 

 comes disharnnonic, whether originally 

 taken from the same or the opposite 

 side). 



(3) If double limbs arise, the original mem- 

 ber (i. e. , the first to begin develop- 

 ment) will have its asymmetry fixed 

 with rule (1) or (2) depending upon the 

 orientation of the graft, while the sec- 

 ondary member will be the 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 em- 

 bryo 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 blastomere of the 2-cell 

 stage (Roux). 



HEMIGONY - one-half egg fragment (Delage, 

 1899). 



