XVI CONTENTS. 



PAGE 



Membranous Tissues . . . .66 



Fibrous Structures . 68 



Primitive Fibrous Tissues . . .68 



Keratose Fibrous Tissues . . 71 



Solid Simple Keratose Fibre . 72 



Spiculated Keratose Fibre . . 73 



Hetro-spiculated Keratose Fibre . . 74 



Multi-spiculated Keratose Fibre 75 



Inequi-spiculated Keratose Fibre . . .75 



Simple Fistulose Keratose Fibre . 75 



Compound Fistulose Keratose Fibre . 76 



Eegular Arenated Keratose Fibre . 77 



Irregular Arenated Keratose Fibre . . 78 



Siliceous Fibre . 78 



Prehensile Fibres . . . .80 



Cellular Tissue . ..81 



ORGANIZATION AND PHYSIOLOGY . 83 



The Skeleton . . 84 



Sarcode ... .88 



The Sarcodous System 90 



The Interstitial Canals and Cavities . 97 



Intel-marginal Cavities . . 100 



Dermal Membrane . 106 



The Pores . 109 



The Oscula . . .112 



Inhalation and Exhalation . .113 



Nutrition . .121 



The Cilia and Ciliary Action . 128 



Eeproduction . . 132 



Gemmules . . 144 



External Gemmulation . . 149 



Propagation by Sarcodous Division . . 149 



Growth^and Development of Sponges . 152 



