CONTENTS 



Introduction page 3 



Material and Methods 5 



Survey of Structure 6 



Classification of the species considered 6 



Order Isospondyli 7 



Suborder Stomiatoidea 7 



Suborder Salmonoidea ......... 27 



Suborder Clupeoidea 3° 



Order Iniomi 3° 



Suborder Myctophoidea 3° 



Suborder Alepisauroidea 43 



Order Miripinnati 43 



Order Cetunculi 43 



Order Giganturoidea .......... 44 



Order Lyomeri ........... 44 



Order Allotriognathi 44 



Order Berycomorphi 45 



Order Percomorphi 48 



Order Pediculati 5° 



Suborder Ceratioidea 5° 



Structure and Systematics 5° 



The larval swimbladder 59 



The swimbladder wall 60 



Mechanical properties of the swimbladder wall 63 



Fat-invested swimbladders 65 



The Swimbladder as a Hydrostatic Organ 68 



The gas-producing complex 69 



The retia mirabilia 69 



The gas-gland 73 



The resorbent part of the swimbladder 78 



Bathypelagic Fishes without a Swimbladder 81 



Vertical Distribution and the Swimbladder 82 



Compressibility of gases 84 



Energy requirements of the swimbladder 84 



Gas requirements of the swimbladder 84 



The Physics and Biology of Vertical Migrations .... 85 



The evidence of vertical migrations 85 



The physical and biological environment 86 



Physical problems 89 



Thermocline crossers 89 



Gas secretion 89 



Gas resorption 9 2 



Partial migrators 94 



Gas secretion 94 



Gas resorption 95 



Pelagic and Benthic Fishes, the Swimbladder, and Aspects of the 



Economy of Deep-sea Life 95 



Summary IJ 3 



References IJ 6 



Plates I-III follotoing p. 122 



