146 DESCRIPTION OF CORALS. 
port his generic character, ‘ Cellule centro in stylum elongato’ (op. cit. Syst. Tables, 
sheet 5), or generic name. It is carefully given by M. Michelin (Iconog. pl. 45. 
fig. 16). At the upper end it was very small, gradually increasing in its down- 
ward course, and it presented, when fully exposed in a vertically fractured star, 
an elongated cone surrounded, towards the base, by the edges of broken lamelle. 
The internal composition was not clearly ascertained, but it was probably solid. 
The immediate lining to the polype-cavities was a thin lamina, with an uneven 
surface, and microscopically punctured. The interspaces between the stars had 
generally little width, and were occupied by vertical and transverse plates, more 
or less perforated by large foramina, and variously united, forming the sub- 
structure of the projecting mounds. 
These surmounting cones were occasionally well-preserved, but were more 
frequently fractured or entirely removed, and sometimes not wholly developed, 
especially on the sides of the stars. In the perfect, completely produced state, 
they were united at the base, constituting an expanded, many-plated, superior 
cup. Respecting their origin, the fine specimen represented in Tab. I. fig. 6. 
proved, at its upper extremity where the stars themselves had scarcely any 
depth, that the cones had been boldly produced, and had taken precedence in 
structural importance of the stellular cavities. The specimen did not afford 
evidence of the mode of earliest development either of these conical interspace- 
tial bodies or of the stars; but it was inferred, that the process was probably 
similar to the one mentioned in the account of the immature margins of Side- 
rastrea Websteri, namely by a lateral extension of the general animal substance. 
The cones which surmounted the deeper, older stars were upward extensions of 
those first formed; and the reticulated structures between the stars, modifica- 
tions of the latter produced by additions to the edges of the component lamine. 
The mounds varied in form and dimensions according to the nature of the sub- 
jacent areas, being generally circular at the angles and elongated on the sides of 
the stars. The lamellee-plates of which they were chiefly composed, decreased 
in breadth, but not in thickness, as they ranged towards the apex. Their cha- 
racters were most fully shown in a specimen belonging to Mr. Edwards’s cabi- 
net, represented by fig. 6 a, and magnified by fig.6 b. Tab. I. They were gene- 
rally straight and singie, but sometimes spirally twisted ; occasionally also a short 
oblique plate united near the base to another which was longer, or two of nearly 
equal height converged and met; in some instances likewise a bifurcation oc- 
curred, a short lamina springing from the side of one of full dimensions. At the 
