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LETTER X. 
MYCETITiE OF WOODWARD PORPITAL AND TURBINATED COM- 
POUND MADREPORITES RAMOSE MADREPORITES MILLEPO- 
RITES CEELEPORITES, &C FOSSIL CORALS OF UNKNOWN 
GENERA. 
The bodies whose nature we shall next inquire into, have fre- 
quently engaged the attention of ory otologists, in consequence, not 
only of their being creatures of a former world, but of the great variety 
of appearances which they yield, and the considerable differences 
which exist between them and any of the recent coral bodies at pre- 
sent known. 
This class of bodies does not appear to have been hitherto examined 
with that attention which they seem to merit. Dr. Woodward, who 
has investigated their structure more carefully than any one else, dis- 
tinguishes them as mycetitcB coralloides, and divides them into mycetitce 
conoides, seu calyciformes, and mycetitce forma compressa, sen discoides. 
But, guided only by their conoidal or discoidal form, he blends the 
simple madreporite, the porpital, and turbinated, each containing one 
star, already examined, (Page 23,) with those of this class, which are 
composed of several stars ; and which, not having been yet separated 
from those other bodies of a somewhat similar form, but of a totally 
different structure, I shall take the liberty to distinguish as porpital 
and turbinated compound madreporites. 
The first of these (the porpital) is of a discoidal form ; it has a 
superior, slightly convex, stellated surface ; and an inferior surface, 
which is generally concave, and finely marked by radiating striee and 
