of the EscHARA. 75' 



And Fig. £, the magnified one of this Incruftation. This 

 belongs properly to the Tubidaria of Lmiceus. 



\ ": 

 N°. 7. Efchara miliepora lapidea^ htjiar pumicis porofa, Piatexxvii. 

 Porous Efchara. 



This ftony Incruftation is often found on the fickle Co- 

 ralline, in irregular Lumps, appearing like white Sand ftrongly 

 united together. But in the Microfcope, it feems to confift 

 of an infinite Number of fmall round Cells, placed in no 

 regular Form, only the circular Entrance to the Cells appears 

 on the Outfide of each ; fo that, in the Microfcope, it looks 

 like a Pumicc-ftone. 



Fig./, N°. 4. exhibits the natural Size of the Cells, which 

 are magnified at Fig. F. But the Incruftation itfelf is often 

 found much larger than the Size of the magnified Part F, 



L 2 C H A P. 



