Mr. W. King on some Families and Genera of Corals. 389 
bifurcating ; radiating from a small root ; running parallel to, and 
at a short distance from each other, on one plane ; and giving off 
bilaterally numerous, short, simple branches, of which opposite 
pairs conjoin midway between the stems arcuately or at an 
ascending angle. Branches occasionally modified into stems. Cel- 
lules on the inner or upper surface of the fronds, on both stems 
and branches, imbricated, and distributed in longitudinal series. 
Series of cellules separated from each other by a dividing ridge. 
(?) Gemmuliferous vesicles on the dividing ridges. 
Type, Retepora virgulacea, Phillips: a Permian species. 
Gen. Phyllopora*, King. 
A Fenestellidia, consisting of infundibuliform, folded, perfo- 
rated fronds or foliaceous expansions. Cedlules on the whole of 
the outer or under surface of the fronds, and planted more or 
less approximating to a position at right angles to the plane of 
the capillary-tubular basal plate. Cellule-apertures with plain 
margins, and parallel to the surface of the fronds. 
Type, Gorgonia Ehrenbergi, Geinitz (= Fenestella permiana, - 
King, Catalogue, p. 6). 
Fam. THAMNISCIDz, King. 
It is proposed to include im this family certain shrub-like ge- 
nera of palzozoic ciliobrachiate corals possessing the bi-struc- 
tural and polypidomial characters of Fenestellide, but having free 
stems and branches. It embraces the two following genera, and 
apparently Mr, M‘Coy’s Ichthyorachis. 
Gen. Thamniscus+, King. 
The typical Thamniscidia. Stems frequently and irregularly 
bifurcating more or less on one plane: celluliferous on the side 
overlooking the imaginary axis of the coral. Cellules imbricated, 
and arranged in quincunx. Gemmuliferous vesicles overlying the 
cellule-apertures. 
Type, Ceratophytes dubius, Schlotheim : a Permian species. 
Gen. Acanthocladiat, King. 
A Thamniscidia. Stems symmetrically and bilaterally branched 
more or less on one plane, rarely bifurcating. Branches short, 
simple, occasionally elongated and becoming bilaterally branched. 
Stems and branches celluliferous on the side overlooking the ima- 
ginary axis of the coral. Cedlules imbricated, and arranged in 
* Etym. pvAdov, a leaf; adpos, a perforation. 
+ Ktym. @apvickos, a little shrub. 
} Etym. dxav6a, a spine; xAddos, a branch: in reference to the spine- 
like branches of the coral. 
