TABLE OF CONTENTS ix 



PAGE 



C. PANCREATIC, GASTRIC, HEPATIC, AND ACCESSORY FORMS OF DIGES- 

 TIVE TISSUES 297 



CHAPTER XVI 

 THE DUCTLESS GLANDS 304 



CHAPTER XVII 



A. THE TISSUES OF RESPIRATION 319 



B. AIR-BREATHING TISSUES OR LUNGS 321 



C. WATER-BREATHING TISSUES OR GILLS 326 



CHAPTER XVIII 

 THE GAS-SECRETING TISSUES OF ANIMALS 333 



CHAPTER XIX 

 THE EXCRETORY OR NEPHRIDIAL TISSUES 339 



CHAPTER XX 



A. INTEGUMENT, MECHANICAL PROTECTION 358 



B. OFFENSIVE MECHANICAL PROTECTION AND THE PRODUCTION OF 



POISONOUS FLUIDS 375 



C. TISSUES THAT PRODUCE LUBRICATING FLUIDS 387 



D. TISSUES THAT PRODUCE ATTRACTIVE AND REPULSIVE ODORS . . 400 



E. TISSUES OF ADHESION AND SPINNING 409 



CHAPTER XXI 



A. TISSUES OF REPRODUCTION . . .418 



B. MALE REPRODUCTIVE CELLS AND NURSE CELLS OF THE SPERMATO- 



ZOON ..... 423 



C. FEMALE REPRODUCTIVE CELLS AND NURSE CELLS OF THE OVUM . 453 



CHAPTER XXII 

 NlDAMENTAL TISSUES, USED TO FORM COVERINGS FOR THE OVA AND 



SPERMATOZOA 478 



ERECTILE TISSUES 490 



CHAPTER XXIII 

 NOURISHING MEMBRANES AND TISSUES OF THE PARENT AND OF THE YOUNG 492 



CHAPTER XXIV 

 TECHNIC 502 



INDEX . 509 



