[ n 5 ] 
XVIII. Obfervdtions on a remarkable Coral- 
line, in a Letter from Mr . John Ellis to 
the Rev . Thomas Birch, D. D . Secret . 
R . S. 
S I R, 
Read March 1 7, "ir BEG leave to prefent you with Tome 
I753 ‘ Jh obfervations, which I have made on a 
coralline, that I lately received from my curious and 
worthy friend Mr. Peter Collinfon. It appears, from 
its fize and firmnefs, to belong to a warmer climate 
than this, and is probably American. 
We find fome of the fame genus, but of a differ- 
ent fpecies, of this coralline, on our own coafts ; but 
they are fmaller, tenderer, and more tranfparent. 
There is one particularly, which comes very near 
this, called by Dr. Dillenius, in the third edition of 
Rays Synopjis , p. 37, N. 20, Tab. II. Fig. 1. Coral- 
lina pumila erelia ramojior : and in Buddie s Hortus 
Jiccus , in the late Sir Hans Sloane's collection, there 
is a fpecimen like it, but not fo fully advanced in its 
ramifications : this he calls Fucus minimus hirfutus 
Jibrillis herbaceis Jimilis , from Doody’ s appendix to 
Rays Synopjis , p. 330. 
This curious fea production, which has the appear- 
ance of a plant, arifes firft from many fmall vermi- 
cular wrinkled tubes, by which it appears to have 
adhered, like curs, to rocks, fhells, fucus’s, or other 
lubmarine fubftances. Thefe tubes uniting form a fort 
of flems, which, as they rife, infenfibly change into 
rows of cells : thefe fcretch out into many regular 
P a dichotomous 
