Mr, ellis on the Gorgonia . 
9 
thus fuccefiive layers are produced. In the fame man- 
ner I fuppofe the concentric circles of the gorgonia to be 
formed, fuccefiive layers of juice exuding from the flefhy 
tubes that furround the hard part or bone of the animal. 
Thus the Item of the gorgonia verticillata , or Minorca 
white Jea-feather , is compofed of different layers of a 
Hi ell-like fubftance (fee fig. 6.), where a broken part of 
the Item is reprefented, and a piece of it magnified, to 
lliew that there is evidently no more communication 
between the different lamime than there is between thole 
of an oyfter-fiiell. In a tranfverfe fe£tion of the gor- 
gonia pretiofa, or true red coral, donati has obferved, 
Philofophical Tranfadlions, vol. XL VII. p. 97. t. 3./. d. 
u Different lines or annual bands, whereof one part is of 
u a rofe colour, another yellowish, others white, others 
u more or lefs charged with colours, that form concen- 
u trie circles like the coats of an onion.” This diver- 
fity of colours could hardly have taken place, had there 
been a circulation of juices through the Item ; and it was 
probably owing to the different food which the animals 
had lived upon at different periods. 
There is another genus of zoophyte , which though it 
fwims freely about in the lea, yet approaches near to the 
gorgonia , and will ferve further to explain the growth of 
its Item, and that is the pennatula , or fea-pen. This ge- 
nus hath a bone along the middle of the infide, which is 
its chief fupport. This bone receives the fupply of its 
ojfeous matter by the fame polype mouths, that furnifh it 
C 
with 
