G. SPONGIA. 185 



ROOT-SHAPED. 



156. Spongia radiciformis. Branching, shapeless, 

 and stiff; branches tortuous, dichotomous, and com- 

 pressed at the summits. 



PROLIFEROUS. 



157. Spongia prolifera. Repeatedly branched and 

 palmated, the digitations distinct ; internally reticu- 

 lated ; the external surface set with small thorns. 



North America. 



OSSIFORM. 



158. Spongia ossiformis. White, and almost branch- 

 ing ; extremity swelled and osculated. 



Sea of Norway. 



MEMBRANOUS. 



159. Spongia membranosa. Somewhat branched; 

 osculated, externally wrinkled or garnished with soft 

 triangular spines. 



Indian Ocean. 



YELLOW. 



160. Spongia fulva. Branching; branches long, 

 cylindrical, about the thickness of a quill or a finger; 

 fibres stiff, fragile, and almost longitudinal. 



American seas. 



FLOWERING. 



161. Sfo^ Gi A Jioribunda. Shapeless; bundles of 

 branches, covered with a chaffy down, and thickest at 

 their extremities. 



Indian Ocean. 



Cor. 2 A 



