CONTENTS. xvu 



PAGE 



ON THE CLASSIFICATION OF THE SPONGIAD^E . . 158 



On the Generic Characters of the Spougiadie . 156 



Tabular View of Systematic Arrangement . . 159 



Order 1. CALCAEEA . . . 160 



Grantia . . . .162 



Leucosolenia . . . 164 



Leuconia . 161 



Leucogypsia ... . 165 



Order 2. SILICEA . 166 



Geodia . 167 



Pachymatisma . . 171 



Ecionemia . .173 



Alcyoncellum . .174 



Polymastia . . . 177 



Halyphysema . .179 



Ciocalypta . . 179 



Tethea . .181 



Halicnemia . . 184 



Dictyocylindrus . 185 



Phakellia . 186 



Microciona . . . 188 



Hymeraphia . . 189 



Hyrnedesmia . . 190 



Hymeniacidon . . 191 



Halichondria . 195 



Hyalonenia . . 195 



Isodictya 197 



Spongilla . 199 



Desmacidon . 200 



Eaphyrus . 201 



Diplodemia . . 201 



Dactylocalyx . . 203 



Farrea 204 



