and Observations on the component Parts of Membrane. 363 



The hardening substance of this was found to be carbonate of 

 lime, with a small portion of phosphate; but the matter form- 

 ing the membranaceous part was (like that of Millepora poly- 

 morpha) in two states ; that of the interior being gelatinous ; and 

 that of the external part being a membrane completely formed, 

 so as to cover the stem, in the manner of a tube. 



The results of the experiments on certain Gorgonice, such as 

 ceratophyta, Flabellum, suberosa, pectinata, and setosa, were not a 

 little remarkable ; for, when the two parts which compose these 

 Gorgonice (namely, the horny stem, and the cortical substance by 

 which it is coated,) were separately examined, it was proved, 



isL That the stems of these Gorgonia consist of a substance 

 analogous to horn ; and that, by long maceration in diluted nitric 

 acid, this horny substance becomes soft and transparent, so as 

 to resemble a cartilaginous or tendinous body ; moreover, the 

 stems of these Gorgonice afford a quantity of phosphate of lime, 

 but scarcely any trace of carbonate. 



2dly. That the cortical part, on the contrary, consists princi- 

 pally of carbonate of lime, with very little or none of the phos- 

 phate ; and the carbonate of lime is deposited in and upon a soft, 

 flexible, membranaceous substance, which seems much to ap- 

 proach the nature of cuticle. 



Some other Gorgonice, which were subsequently examined, 

 and which much resembled the former in construction, did not 

 yield any phosphate of lime ; but in every other particular they 

 proved to be similar. 



The Gorgonia Antipathes was found to be entirely formed of 

 a fibrous membrane ; and the black shining polished Gorgonia 

 afforded, by maceration, a most beautiful specimen of mem- 

 branes concentrically arranged. 



