[ 359 ] 
VII. On the Structure and Development of Lepidosteus. 
By F. M. Balfour, LL.D., F.R.S., Fellow of Trinity College , Cambridge, and 
W. N. Parker, Assistant in the Biological Laboratory of the Normal School of 
Science , South Kensington. 
Received November 24,—Read December 8, 1881. 
[Plates 21-29.] 
Table of Contents. 
Page. 
Introduction . 360 
General Development ..,. ,. ... 360 
Brain— 
Adult brain. 374 
Development of the brain. 378 
Comparison of the larval and adult brain of Lepidosteus, together with some 
observations on the systematic value of the characters of the Ganoid 
brain . 380 
Sense organs— 
Olfactory organ. 383 
Anatomy of the eye. 383 
Development of the eye . 384 
Suctorial disc . 385 
Muscular system . 386 
Skeleton—- 
Vertebral column and ribs of the adult. 386 
Development of the vertebral column and ribs. 388 
Comparison of the vertebral column of Lepidosteus with that of other forms 398 
The ribs of Pishes. 399 
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. 405 
Excretory and generative organs—• 
Anatomy of the excretory and generative organs of the female ... 411 
Anatomy of the excretory and generative organs of the male .. 413 
Development of the excretory and generative organs. 415 
Theoretical considerations . 420 
The alimentary canal and its appendages— 
Topographical anatomy of the alimentary canal. 424 
Development of the alimentary canal and its appendages . 426 
The gill on the hyoid arch. 429 
The systematic position of Lepidosteus . 430 
List of memoirs on the anatomy and development of Lepidosteus . 433 
List of reference letters. 434 
Explanation of plates. 436 
MDCCCLXXXII. 3 A 
