400 Maximilian Herzog. 



attention to a misconception of the writer as to certain relations 

 of the amnion and jolk sac. It is needless to say that the con- 

 ception of Professor Hubrecht proved to be the correct one. This 

 necessitated on the part of the author a careful re-examination of 

 the sections and some changes in the manuscript for the Transac- 

 tions of the Congress. 



Professor C. S. Minot then kindly placed at my disposal his 

 laboratory and his library to enable me to make the necessary re- 

 examinations and changes. To him, as also to Professor F. T. Lewis, 

 I am under obligations for the great kindness shown on this occasion, 

 and in the final revision of the manuscript. 



The literature on human placentation is extensively given in 

 Keibel's ISTormentafeln ; in Peters' monograph ; in Webster, ''Human 

 Placentation" ; in Pf annenstiel's article in Winkel's ''Handbuch der 

 Geburtshiilfe." The most recent contributions are quoted in Jung's 

 monograph and Bryce and Teacher (1. c). Stahl, in his article 

 on "Die Embryonalhiillen der Sanger und die Placenta," in Vol. I, 

 Part 2, Hertwig's "Handbuch der Entwiekclungslehre der Wirbel- 

 thiere," gives the literature on placentation among mammals in 

 general. 



