XXII. ON THE STRUCTURE AND DEVELOPMENT OF LEPI- 

 DOSTEUS 1 . By F. M. BALFOUR and W. N. PARKER. 



(With Plates 3442.) 

 TABLE OF CONTENTS. 



PAGE 



INTRODUCTION 739 



GENERAL DEVELOPMENT 74 



BRAIN 



Adult brain 759 



Development of the brain . . _ 7^4 



Comparison of the larval and adult brain of Lepidosteiis, together with 

 some observations on the systematic value of the characters of the 

 Ganoid brain 767 



SENSE ORGANS 



Olfactory organ 77 ' 



Anatomy of the eye H>. 



Development of the eye 771 



SUCTORIAL Disc 774 



MUSCULAR SYSTEM 775 



SKELETON 



Vertebral column and ribs of the adult 77^ 



Development of the vertebral column and ribs 778 



Comparison of the vertebral column of Lepidosteus with that of other 



forms 79 3 



The ribs of Fishes 793 



The skeleton of the ventral lobe of the tail fin, and its bearing on the 



nature of the tail fin of the various types of Pisces . . . 80 1 



EXCRETORY AND GENERATIVE ORGANS 



Anatomy of the excretory and generative organs of the female . 810 



Anatomy of the excretory and generative organs of the male . 813 



Development of the excretory and generative organs . . . . 815 



Theoretical considerations 822 



1 From the Philosophical Transactions of the Royal Society, 1882. 



