CLASSES. 
1st Class. Celluliferous Polypidoms in non -irri- 
table cells.— 3 Orders. 
2nd Class. Calciferous Polypidoms. Calcareous 
substance, united with animal substance, or incasing 
it : apparent in all circumstances. — 3 Orders. 
3rd Class. Corticiferous Polypidoms, composed 
of two substances ; one exterior and enveloping, called 
Rind, or Incrustation ; the other named Axe, placed 
within, and supporting the first.— 3 Orders. 
4th Class. Carnoid Polypidoms. A fleshy mass, 
wholly animated, covered with polypi, but having no 
central axe.— No Order. 
