viii PROBLEMS OF FERTILIZATION 



assaults suggest co-operation such as is carried out at the 

 Marine Biological Laboratory of Woods Hole. A large 

 share of recent work on the subject has as a matter of 

 fact been done in this institution, including the writer's 

 own work and that of numerous other authors cited 

 below. 



Chapter i is reprinted slightly modified from an 

 address delivered before the American Society of Natu- 

 ralists and the Zoological Section of the American Asso- 

 ciation for the Advancement of Science, December 30, 

 1915, published in Science, N.S., Vol. XLIII, Jan- 

 uary 14, 1916. 



