BATTERSBYIA, PALCEOCYCLUS, AND ASTEROSMILIA. 
651 
together in a division of the Astrceidce, and to place it near the above-mentioned meso- 
zoic genera under the name of Palastrceacece. 
4. Genus Palasocyclus*. Plate XXXII. figs. 6 a-6 e. 
This genus of Silurian corals has hitherto been regarded as belonging to the Fungidce , 
and as the only representative of that great family in the palseozoic rocks. It is rather 
anomalous that a number of species of a highly organized coral genus should be found 
in the Silurian rocks of Dudley, Wenlock, and of Gothland, and that not a species of any 
other genus of the family of the Fungidce should have been found in the Devonian or In 
the Carboniferous and Permian strata. The doubt whether Palceocyclus could belong 
to the Fungidce was rendered more worthy of consideration by the discovery in the 
Australian tertiaries of a simple fungoid coral which had all the generic attributes of 
the Palseozoic genus f. 
Careful sections of specimens of Palceocyclus porpita, Linnaeus, sp., and Palceocyclus 
rugosus , Milne-Edwards and Jules Haime, were made, and it became evident that, 
although the external characteristics of the corals were those of the simple Fungidce, the 
internal structure was analogous to that of the Palseozoic family of the Cyathophyllidce. 
The generic diagnosis of Palceocyclus is as follows. 
The corallite is simple, short, and in general discoid, it is free and subpedicellate. 
The wall is covered with a complete epitheca. The calice is circular, and has a well- 
marked central fossa. The columella is rudimentary. The septa are moderately nume- 
rous, stout, straight, slightly exsert, and free internally. They are granular laterally, 
and dentate superiorly. 
In order to admit the genus into the family of the Fungidce , the septa of all its species 
must have synapticulee upon them, and the corallites should not possess curved dissepi- 
ments or tabulee. 
Transverse and longitudinal sections of Palceocyclus porpita and Palceocyclus rugosus 
were prepared, and the absence of synapticulee was proved, as was also the presence of 
an inclined dissepimental endotheca at the sides, and of tabulae in the centre of the 
corallites. 
The taller the specimen the more numerous were the tabulae, and the uppermost of 
them formed the base of the septal fossa. In the discoidal species no tabulae could be 
distinguished, but there were some marked rugose peculiarities and no synapticulee. 
The septa of Palceocyclus are ornamented laterally with ascending rows of granules or 
blunt dentations. When the septa are worn from above downwards, these ornamenta- 
tions stand out on either side of the laminae and give the appearance of synapticulae. 
Transverse sections through the corallites show the adhesion of the dissepiments to the 
septa ; but the cross-bar-like appearance is produced by the section passing through a 
* Miene-Edwards et Jules Haime, Compt. Rend, de l’Acad. des Sc. t. xxix. p. 71, 1849. Hisinger’s Cyclo- 
lites. 
t Ann. and Hag. of Nat. Hist. Sept. 1864, plate vi. fig. 2. 
MDCCCLXVII. 4 U 
