126 DESCRIPTION OF CORALS. 
broad lamellz ; terminal cup formed by upper edges of lamelle, convex on the 
outer half, concave on the inner, central boss more or less prominent, round or 
compressed, coated with minute tubercles. 
Lamk. Anim: s.’Veert..ed. 1. t. ii.;p. 231, 18165 ed) 25 tip, S61, 1836: 
Schweigger, Beobach. t. vu. f. 65. Expl. Plates (Turb. elliptica ?). Cuv. et Bron- 
gniart, Oss. Foss. nouv. ed. t. ii. p. 269. pl. 8. f. 3, 1822. Lamx. Exp. Méth. 
p-. 51. pl. 74. f. 18-21, 1821. Goldfuss, Petref. p. 51. pl. 15. f. 3, 1826-33. 
De France, Dict. Sc. Nat. t.lvi. p. 93, 1828. De Blainville, Man. d’Act. p. 341 
(Atlas, pl. 57. f. 2 2), 1830-34. Michelin, Iconog. p. 151. pl. 438. f. 4, 1844-45. 
The Bracklesham collection included two Turbinolie referable to this species ; 
and they are both represented in Tab. I. fig. ] & 1*, for the purpose of showing 
variations in form, where vertical dimensions are similar. The more slender 
specimen (fig. 1) was apparently older than the other, the secondary or narrow 
lamellze being fully developed and united to the six broadest plates ; while in the 
thicker coral (fig. |*) they were only rudimentary. In the latter case, the interior 
as well as the exterior had been subjected to friction ; but the edges of the inci- 
pient lamellz were sharp, and most prominent near the margin of the cup. An- 
other character may perhaps be worthy of consideration as indicative of the 
number of lamella, which may exist in some specimens. The ribs are generally 
of unequal downward extent, or alternately of great length and shorter dimen- 
sions, the latter agreeing in position with the narrow lamelle (fig. 1 6 & 1* b), and 
being apparently precursory developments, existing sometimes greatly anterior 
to the first signs of the corresponding internal plates, as in the wider coral (fig. 1*), 
where they commence near the base. In a beautiful, finely-preserved French 
Turb. sulcata, 5 lines in height, kindly lent me by Mr. Pratt, F.G-S., twenty-four 
ribs, answering to the twenty-four lamellz, had a similar range to those in the 
thick Bracklesham example (fig. 1*) ; but near the upper extremity twenty-four 
short intermediate ribs were displayed. There was not the slightest indication 
of an accompanying internal plate, but it was conceived that such a structure 
would have been produced, had the specimen attained its full dimensions ; and 
then the terminal star would probably have been perfectly symmetrical, or com- 
posed wholly of three-plated groups. The cross-bars between the ribs were im- 
perfectly shown in the English specimens ; and, where best preserved, they dif- 
fered somewhat from the ordinary characters, having even less regularity and 
boldness than is usual, and partaking to a much greater extent of the nature of 
those which precede the introduction of new ribs. 
