it comprehends the Flustreas, Cellarias, &c. The se- 

 cond Order includes all those with coalescent or 

 united cells, formerly all styled Sertularia. The Tu- 

 bularia forms the third Order, their cells being tubular 

 and horny, simple or branching, with one or many 

 openings. 



The second Class, whose Polypidoms are styled 

 Calciferous, are of a calciferous substance, mixed 

 with that of animal, and continuing apparent in every 

 stage, contains also three Orders ; the first of which 

 has, like the Tubularias, the polypi at the extremities 

 of the stems and branches, but, being less horny and 

 more calcareous, forms an intermediate link between 

 the last Order of the preceding Class and the second 

 Order of the present Class, whose Polypidoms are 

 very cretaceous or chalky, but whose polypi are not 

 apparent ; they are articulated. The third Order 

 of this Class are not articulated. 



The Polypidoms of the third Class are termed Cor- 

 ticiferous : they are composed of two substances, the 

 one exterior, and enveloping, named rindy or in- 

 crustation ; the other called axe, placed in the centre 

 of the first, and supporting it : it is also divided into 

 three Orders. The first Order comprehends the 

 Spongia, whose polypi are dubious, but decidedly 

 invisible. The second includes the genera of the 



