654 
MR. P. MARTIN DUNCAN ON THE GENERA HETEROPHTLLIA, 
irregular in their development, and crests are occasionally present. The septa are 
numerous and exsert. The columella is more or less solid, essential, and compressed. 
Pali exist. The endothecal dissepiments are distinct, tolerably numerous, and are curved. 
The genus forms the link in the classificatory chain between the genera Placosmilia, 
Parasmilia , and Trochosmilia and the genera Placocycitlms , P aracyathus, and Trocho- 
cyatlms. As it cannot be correctly associated either with the TurMnolidce or the Tro- 
chosmiliacece , it must be included in a new division — the Aster osmiliacece. 
6. It has been attempted to prove the necessity of classifying the genera, the anatomy 
of whose species has been described in this communication, as follows. 
Heterojyliyllia , M £ Coy, must be associated with Pattersbyia , Ed. et H., in a division of 
the Astrceidce— the Palastrceaceoe. 
The genus Palceocyclus , Ed. et H., must be abolished and its species added to the 
genus Cyathophyllum , Goldfuss. 
The genus Asterosmilia , nobis, forming the link betAveen the simple Astrceidce and the 
TurMnolidce, should form the division Asterosmiliacece, and should be placed betAveen the 
Trochosmilice, Placosmilice, and Parasmilice and the Trochocyathi , Placocyatlii, and 
PciracyatJii. 
By the absorption of the genus Palceocyclus a representative of the tertiary coral-fauna 
is removed from the Palaeozoic ; and by the separation of Pattersbyia from the Mille- 
jjoridce, and its association with Heterophyllia, formerly a genus incertae sedis, in a division 
of the Astrceidce, tAvo genera Avith mesozoic affinities are introduced into the Palaeozoic 
coral-fauna. 
March 1867. 
On April 20, 1867, the author added the genus Pentaccenia to those allied to Patters- 
byia, and corrected the description of the gemmation of Pattersbyia gemmans. 
Explanation op the Plates. 
PLATE XXXI. 
Fig. 1 a. A portion of the corallum of Ileterojg hy Uia granulata, sp. nov. 
b. Magnified vieAV of a transverse section, showing the septa and the Avail. 
c. Magnified view of the granular costae. 
cl. The wall magnified, Avith a septum and an endothecal dissepiment. 
e. The curved arrangement of the costae. 
Fig. 2 a. A portion of the corallum of Heterophyllia angulata, sp. nov. 
b. A transverse section : magnified. 
c. The wall, septa, and dissepiments : magnified. 
d. A longitudinal section shoAving the dissepiments : magnified. 
