GLOSSARY 511 



PRE-FOR-MA'-TION. The doctrine that the fully formed organ- 

 ism exists in the germ, and that development is merely 

 its unfolding. 



PRE-IN-DUC'-TION. A modification of the second filial gener- 

 ation caused by the action of environment on the germ 

 cells of the parental generation. 



PRE-PO'-TEN-CY. The preponderance of one parent over the 

 other in the transmission of hereditary characters. 



PRI'-MATES. The highest order of mammals, including monkeys, 

 apes, and man. 



PRIMITIVE SEX CELLS. The earliest recognizable progenitors 

 of the sex cells in development. 



PRO'-TE-IN. Complex organic substances containing nitrogen, 

 e.g. white of egg. 



PRO-TE'-NOR. A genus of the true bugs. 



PRO'-TO-PLASM. The living material of an organism. 



PRO-TO-ZO'-A. The simplest animals, usually consisting of a 

 single cell. 



PY-LO'-RUS. The narrow opening between stomach and 

 intestine. 



RECESSIVE CHARACTER. An inherited character which remains 

 undeveloped when mated with a dominant character. 



REDUCTION-DIVISION. That maturation division in which the 

 number of chromosomes is halved. 



REFLEXES. Relatively simple, automatic responses. 



RESPONSE. Any activity of an organism called forth by a 

 stimulus. 



REVERSIONS. The sudden reappearance of long-lost racial 

 characters. 



SEGREGATION. The separation of dominant and recessive char- 

 acters in the offspring of hybrids. 



SELF DIFFERENTIATION. Differentiation due chiefly to intrinsic 

 causes. 



SENSITIVITY. Capacity of receiving and responding to stimuli. 



SEX CHRO'-MO-SOME. The "odd" or accessory chromosome 

 which is supposed to determine sex. 



SEX-LIMITED. Any character which is found in one sex only. 



