THE EARLY DEVELOPMKXT OF THE M.\RS[JPIALIA. 



The Early Development of the Marsupialia, with 

 Special Reference to the Native Cat (Dasy- 

 urus Viverrinus). 



(Contributions to the Embryology of the Marsupialia, IV.) 



By 

 J. P. Hill, D.Sc, 



Jodrell Professor of Zoology and Comparative Anatomy, University 

 of London. University College. 



With Plates 1-9 and 2 Text-figs. 



Table of Contents. 



PAGE 



Introduction . . . . . -2 



Chapter I. — Critical Review of Previous Observations 



on the Early Development of Marsupialia . . 5 



11 

 11 

 21 

 23 

 25 

 28 

 28 

 37 



Chapter II. — The Ovum of Dasyurus 



1. Stiiictnre of Ovarian Ovum . 



2. Matiu-ation and Ovulation . 



3. Secondary Egg-membranes . 



4. Uterine Ovvini 

 Chapter III. — Cleavage and Formation of Blastocyst 



1. Cleavage .... 



2. Formation of Blastocyst 

 Chapter IV. — Growth of Blastocyst and Differentia- 

 tion OF the Embryonal Ectoderm and the Entoderm 43 



1. Growth of Blastocyst . . .43 



2. Differentiation of the Embryonal Ectoderm and 



the Entoderm . . . .52 



3. Establishment of the Definitive Embryonal Area 65 



4. Summary . . . .72 

 Chapter V. — Some Early Stages of Perameles and 



Macropus . . . . . .74 



VOL. 56, PART 1. — j;ew series. 1 



