VI 



TABLE OF CONTENTS. 



1876 

 IX. On the spinal nerves of Amphioxus . 



187678 



X. A Monograph on the development of Elasmobranch 

 Fishes. With Plates 621 



1878 



XI. On the phenomena accompanying the maturation and 

 impregnation of the ovum ...... 



XII. On the structure and development of the vertebrate ovary. 

 With Plates 24, 25, 26 



1879 



XIII. On the existence of a Head-kidney in the Embryo Chick, 



and on certain points in the development of the 

 Miillerian duct. By F. M. BALFOUR and A. SEDGWICK. 

 With Plates 27 and 28 



XIV. On the early development of the Lacertilia, together with 



some observations on the nature and relations of the 



primitive Streak. With Plate 29 .... 



XV. On certain points in the Anatomy of Peripatus Capensis . 



XVI. On the morphology and systematic position of the 



Spongida 



1880 



XVII. Notes on the development of the Araneina. With Plates 



30, 3i, 32 



XVIII. On the spinal nerves of Amphioxus 



XIX. Address to the Department of Anatomy and Physiology 

 of the British Association for the Advancement of 

 Science 



PAGE 

 197 



203 



521 

 549 



618 



644 



657 



661 



668 

 696 



1881 



XX. On the development of the skeleton of the paired fins of 

 Elasmobranchii, considered in relation to its bearings 

 on the nature of the limbs of the Vertebrata. With 



Plate 33 714 



XXI. On the evolution of the Placenta, and on the possibility of 

 employing the characters of the Placenta in the classi- 

 fication of the Mammalia 734 



