262 



not exceed that of the grains of the fence. Although these bear 

 no sort of proportion, compared with the ten strong lamellfe, still, 

 for reasons that it would take some time to tell, I am inclined to 

 look on them as true lamella, in a rudimentary stage. In some 

 calicles they cannot be discovered at all ; in others there are two, 

 and, in rare instances, there are as many as ten, or one between 

 each pair of large lamellae. A vertical section of a calicle shows 

 the characteristic dissepiments {traverses, Edw.) of a true As- 

 trsean, and a styliform columella, which continues nearly, or 

 quite, to the bottom, though with a diminished size towards its 

 lower extremity. In this species the columella gives the same 

 indication of a bilateral symmetry that is shown in the elongated 

 mouth of Actinia, and, among the Halcyonoids, in that of Renilla, 

 &c. In a line with the longest diameter of the columella there 

 are, almost always, two lamellie, and, on each side of the axis 

 thus formed, four lamella? symmetrically arranged ; and it is to 

 be further observed, that the calicle itself has a tendency to elon- 

 gate itself in the direction of this axis. The corallum is covered 

 underneath with a thin, slightly folded epitheca ; and above it 

 has a rough look, under a lens, by reason of its crowded calicles, 

 and stout, exsert lamella?. 



Now, as regards the place this species should occupy among 

 Astreidffi, if we go by the system of Dana, it would come under 

 the Genus Astrjea, and would be among the species of the Sub- 

 Genus Orbicella, from which it differs only in the less numerous 

 rays. If, on the other hand, we refer to Edwards and Haime, 

 we find that it agrees with no living genus, but is \qyj near to, 

 if not identical with, the Genus Astroccenia, which is entirely 

 fossil, and, with the exception of one species, does not rise higher 

 than the chalk. With this genus it agrees in growing in a plate; 

 in having an epitheca a little folded ; in marginal budding ; in 

 polyps soldered by their walls ; in a solid, styliform columella ; 

 in having thick lamella*, and in having small calicles. If the 

 genera of Edwards are really to be admitted, it would be curious 

 to see this old habitue of the chalk once more among the living. 

 A description of the genus will be found in the Annales des Scien. 

 Nat. S*^™*^ Serie, tome x. page 296, and figures in the Paleonto- 

 graphical Society Monograph on British Fossil Corals, 1850, 

 Part I. Plate 5 ; and in Denkschriften der Akademie zu Wien, 



