CONTENTS xv 



PAGE 



GILLS (continued) 



of Fishes . 276 



of Dipnoans 278 



of Amphibians 279 



II. AIR-BLADDER AND LUNGS . . . 280 



1. AIR-BLADDER 280 



2. LUNGS .281 



Air Tubes and Larj r nx 283 



of Dipnoans 283 



of Amphibians 283 



of Reptiles >, . 284 



of Birds 285 



of Mammals , 286 



Lungs proper 288 



of Dipnoans ; 288 



of Amphibians 288 



of Reptiles ..;.... 290 



of Birds 291 



of Mammals 296 



ABDOMINAL PORES 298 



H. ORGANS OF CIRCULATION 299 



General Description and Development 299 



Heart, together with Origin of Main Vessels 305 



of Fishes 305 



of Dipnoans 307 



of Amphibians 309 



of Reptiles 313 



of Birds and Mammals 315 



Arterial System 319 



Venous System 322 



of Fishes . ... 322 



of Dipnoans 326 



of Amphibians .......... 328 



of Amniota 328 



Retia Mirabilia 333 



Lymphatic System 333 



MODIFICATIONS FOR THE INTER-UTERINE NUTRITION OF 



THE EMBRYO : FCETAL MEMBRANES 336 



1. Anamnia 336 



2. Amniota 337 



I. URINOGENITAL ORGANS 341 



General Description and Development 341 



Male and Female Generative Ducts 347 



Gonads . 347 



