CONTENTS OF PART I. 



*Mr F. M. Balfour and Mr A. Sedgwick. — On the Existence 

 of a Head-kidney in tlie Embryo Chick and on some 

 Points in the Development of the MuUerian Duct. 

 Plates I. and II. ....... 1 



*Mr F. M. Balfour. — On the Early Development of the Lacer- 

 tilia, together with some Observations on the Nature 

 and Relations of the Primitive Streak. Plate III. . 21 



**Mr F. M. Balfour. — On Certain Points in the Anatomy of 



Peripatus Capensis . . . . . . .31 



*Mr W. B. Scott and Mr Henry F. Osborn. — On some Points 



in the Early Development of the Common Newt . . 34 



*Mr Adam Sedgwick. — Development of the Kidney in its 



Relation to the Wolffian Body in the Chick . . 62 



*Mr F. M. Balfour. — Notes on the Development of the 



Araneina ......... 83 



**Mb Adam Sedgwick. — On the Development of the Struc- 

 ture known as the ' Glomerulus of the Head-kidney' in 

 the Chick 107 



N.B. — The papers marked with one asterisk are reprinted from 

 the ' Quarterly Journal of Microscopical Science,' those with two 

 asterisks, are reprinted from the * Proceedings of the Cambridge 

 Philosophical Society.' 



