590 FRANK R. LILLIE 



Robertson, T. B. 1912 Studies in the fertilization of the eggs of a sea-urchin 

 (Strongylocentrotus purpuratus) by blood-sera, sperm, sperm-extract 

 and other fertilizing agents. Archiv f. Entw'mech. d. Organismen, 

 Bd. 35, pp. 64-130 (see pp. 80-82). 



Wilson, E. B. 1903 Experiments on cleavage and localization in the Nemertine 

 egg. Archiv f. Entw'mech. d. Organismen, Bd. 16, pp. 411-460 (see 

 pp. 417-419). 



