Mr. J. Young on Ure’s “Millepore.”’ 155 
after referring to the several paleontologists who had noticed 
the structure of this organism, he describes some sections that 
he had prepared, and which are figured in plate xi. figs. 1 to 3. 
At page 195 he says, “ This is probably the fossil figured 
by Ure in his ‘ History of Rutherglen and East Kilbride’ 
(pl. xx fig. 1), and described by Fleming as Cellepora Urii 
(Brit. Animals, 1828, p. 533). If this is so, Ure was the first 
to figure Chetetes tumidus; and it, like many of his figures, 
is very faithfully drawn.” 
Recently I have discovered what I believe to be an impor- 
tant internal character in the structure of the organism 
which Ure figured and described in 1793 as a species of 
“ Millepore,” and which will, I think, be the means of 
distinguishing it from Phillips’s species, with which it has 
all along been confounded, from the great resemblance of the 
external characters in the two organisms. 
This new character consists of a series of thin, perforated 
tabule that exist in the outer portion of the tubes of the 
larger corallites. The perforation or central opening in these 
tabule is of a roundly crescentic or reniform shape, and has 
a thickened edge or rim around its margin, its diameter being 
one third the width of the tubes. The concave edge of the 
opening in branching specimens is invariably turned towards 
the lower end of the branches; so that from this feature in the 
form of the perforation one is always able, in fragments, to 
say which was the lower or upper end of any branch in speci- 
mens where it could not be so determined from any of the 
other characters seen on the surface. 
The tabule are numerous, their number varying from five 
to eight in each corallite, they being only about the diameter 
of the tubes apart, and are apparently confined to the outer 
portion, where the tubes bend from the nearly vertical posi- 
tion they occupy within the centre of the branches to open at 
right angles on the surface. 
{ first discovered this new character in thin incrusting speci- 
mens of the organism, which seems to be its first or earliest 
stage, and in which it is generally found attached to stems of 
erinoids, corals, and shells, in spot-like crusts that vary in 
size from one fourth of an inch to two or more inches in length, 
From this first thin incrusting stage the organism afterwards 
grew, in a branching manner, as described by Ure, until it 
attained a height, as seen in some specimens, of more than 
3 inches. ‘The branches, which are dichotomous and have 
rounded extremities, seldom exceed more than from 2 to 3 
lines in diameter, their section varying from round to oval; but 
they are often found much crushed whenimbedded in soft shale. 
