FERTILIZATION ON PARTHENOGENESIS. 177 



3. Sperm having entered these eggs appear only as foreign 

 bodies. They do not cause the production of asters, nor are 

 cleavage spindles produced. 



4. The lysin theory of fertilization is found inadequate to 

 explain the results. 



5. Eggs over-exposed to butyric acid are still capable of a 

 certain amount of fertilization, though the process is usually 

 very abnormal. No membranes are produced. Polyspermy is 

 extremely frequent. 



6. Exposure to butyric acid for ten minutes leads to a non- 

 fertilizable condition of the egg. Sperm enter but are non- 

 effective and non-effected. 



7. Eggs subjected to a temperature of 35 C. for 10 minutes 

 are rendered non-fertilizable. Sperm enter the eggs, part 

 disintegrating in fragments, part forming large clear vesicles 

 and part apparently remain unaffected. 



8. Where fertilization is possible fertiliz'n has always been 

 found present. Where fertilization is not possible fertilizin has 

 never been found. 



9. The quantitative aspect of fertilization is very definitely 

 indicated. 



10. Superposition of fertilization upon parthenogenesis, where 

 activation has been complete (indicated by full membrane pro- 

 duction and absence of fertilizin) is impossible. 



Where activation by parthenogenetic agents has been only 

 partially completed, partial fertilization is yet possible, but 



development is usually abnormal. 

 April 15, 1916. 



VIII. LITERATURE CITED. 



Allyn, Harriet M. 



'12 The Initiation of Development in Chaetoperus. BIOL. BULL., Vol. 24, 



p. 22-72. 

 Delage, Yves. 



'99 Etudes sur la Merogone. Archiv. de zoologie Exper. et Gen., 3d Ser., 



Tome 7. 

 '01 Etudes experimentales sur la maturation cytoplasmique et sur la partheno- 



genese artificielle chez les Echinodermes. Archiv. de zool. Exper. et Gen., 



Ser. 3, T. 9- 

 Glaser, Otto. 



'14 A Qualitative Analysis of the Egg secretions and Extracts of Arbacia and 



Asterias. BIOL. BULL., Vol. 26, p. 367-386. 



