THE INITIATION OF DEVELOPMENT IN 

 CH^TOPTERUS. 



HARRIETT M. ALLYN. 



Page 



I. Introduction 22 



II. First changes in development 27 



III. Study of artificial parthenogenesis in Chcetoplerus by means of single 



agents 30 



A. The action of salt solutions 30 



1. Potassium chloride 30 



2. Sodium chloride 35 



B. Acids 36 



C. Alkali 37 



D. Alcohol 37 



E. Potassium cyanide 38 



F. De-aerated sea-water 38 



G. Excess of oxygen in the sea-water 38 



H . Temperature changes 39 



1. Cold 39 



2. Heat 39 



IV. Combination of two agents 4 2 



A. Artificial parthenogenesis supplemented by fertilization 42 



1. Potassium chloride and sperm 42 



2. Cold and sperm 46 



3. Excess of oxygen in the sea-water and sperm 47 



B. Combination of two physico-chemical agents 48 



1. Double potassium chloride 48 



2. Oxygen and potassium chloride 48 



3. Heat and potassium chloride 49 



4. Cold and potassium chloride 50 



5. De-aerated sea-water and potassium chloride 51 



6. Potassium chloride and sea-water de-oxygenated by a stream 



of hydrogen 5 1 



7. Potassium cyanide and potassium chloride 51 



8. Sodium chloride and sodium hydroxide 



V. Discussion 



1. Problem of the first changes 



2. Problem of maturation 54 



3. Problem of differentiation 



4. Problem of cleavage OI 



5. Artificial parthenogenesis supplemented by fertilization . 63 



6. Combination of two physico-chemical agents 64 



7. Summary of discussion 



21 



