LECTURE IX. 

 AMPHIMIXIS. 







Amphimixis consists in fusion of chromatin in two 

 cells prepared for the process. Sex cells fundament- 

 ally alike. This is shown in : 



1. Their origin. 



2. Conjugation of equal protozoa. 



3. Homology of spore-producing organs. 



4. Low feeding produces males ; high feeding, fe- 

 males. 



5. Maupas's experiment : Heat produces males ; 

 cold, females. 



6. Parthenogenesis of male cells ; produces weak in- 

 dividuals from lack of food substances. 



7. Formation of sex cells in male and in female by 

 division of mother cell into four. 



Two phenomena (first noticed by Harvey, 1651) : 



1. Heredity ; mixture of parental character in off- 

 spring, through mixture of idants ( ah nen plasma) car- 

 ried in the chromatin. 



2. -Sex differentiation, in growth of individual after 

 the cell-growth has begun and idants are mixed. 



Units of heredity. Their combinations infinite. 



Galton's estimate : Twenty-five per cent, from each 

 parent ; six and two-thirds per cent, from each grand- 

 parent ; remainder unidentified variation and at- 

 avism. 



