GLOSSARY 617 
Factor.—An independently inheritable element of the genotype by the presence of 
which some particular character in the organism is made possible; gene. Sometimes 
referred to as genetic factor or unit factor to avoid possible misinterpretation. 
Fecundity.—The potential reproductive capacity of individuals; the ability to 
produce mature ova or sperm. 
Feral.—Run wild, having escaped from domestication and reverted to a state of 
nature. 
Fertility—Ability to produce normal, living young; the opposite of sterility. 
Fertilization.—The union of male and female sex cells. 
Filly.—A female colt or foal. A young mare. 
Fluctuations (Fluctuating Variations).—The slight differences normally found in 
organisms and attributed etther to environmental influences or to recombinations of 
genetic factors. 
Fetus.—An animal embryo in the later stages of development. 
Forehand.—That part of the horse which is before the rider. 
Gamete.—A mature male or female sex cell. 
Gametogenesis.—The process of development of mature sex cells from the pri- 
mordial germ tract. 
Gene.—See factor. 
Genetic Factor.—See factor. 
Genotype.—The constitution of an organism with respect to the factors of which 
it is made up; the sum of all the genes of an organism. 
Genus (pl. Genera).—In botany and zoology a classificatory group ranking next 
above the species, containing a group of species (sometimes a single species) possessing 
certain structural characters different from those of any others. 
Germ.—In contrast with soma, the germ-plasm. 
Germ Cells.—Cells specialized for sexual reproduction; the ova and spermatozoa 
in animals, the egg cells and pollen grains in plants. 
Germ-plasm.—That part of the cell-protoplasm which is the material basis of 
heredity and is transferred from one generation to another. 
Geotropic.—Turning or inclining toward the earth. 
Graft-hybrid.—A shoot or plant produced by grafting one kind of plant upon 
another and whose characters are intermediate between the characters of the two 
components. 
Graft-symbiont.—One member of a graft union. 
Gynandromorph.—An animal in which one side exhibits female characters and the 
other side, male characters. 
Haploid.—The number of chromosomes normally found in the gametes of an indi- 
vidual; one-half the somatic or diploid number. 
Heifer.—A young cow that has not had a calf. 
Hereditary-complex.—The total set of factors in any species conceived as a re- 
action system in which the factors display harmonious interrelations with one another. 
Hermaphrodite.—Being of both sexes. 
Heterosynapsis.—As applied to the sex-chromosomes, the pairing of an X- and a 
Y- or a W- and a Z-chromosome. 
Heterotypic Division.—The meiotic or true reduction division by which homolo- 
gous chromosomes are separated into different gametes. 
Heterozygosis.—The condition of an organism due to the fact that it is a heterozy- 
gote; the state of being heterozygous; the extent to which an individual is hetero- 
zygous. 
Heterozygote.—A heterozygous individual. 
Heterozygous.—That condition of an individual in which any given genetic factor 
Digitized by Microsoft® 
