68 Geological Society. 
2. “ Thamniscus: Permian, Carboniferous, and Silurian.” By 
George W. Shrubsole, Esq., F.G.S. 
After a sketch of the genus, represented by one Permian, possibly 
two Carboniferous, and one Silurian species, the author discussed 
certain peculiarities claimed for the Permian form by the founder of 
the genus, Prof. King, viz. certain “ denticles, vesicles, and hemi- 
spheric bodies, similar to those observed in Ceéllaria salicornea.” 
These the author failed to find, but observed on the cell-face of this 
form a strong defensive spine, hollow at the base, which, when worn, 
gave an appearance which resembled the above structures. A 
denticle-like process also seems only to be the unequal wearing 
down of the cell-mouth. ‘The author redescribed the genus, as 
well as a new Silurian species, for which he proposed the name of 
Thamniscus antiquus. It is from the Dudley limestone, and is in 
the Woodwardian Collection at Cambridge. It is not rare, but is 
generally too fragmentary for description. 
3. “On the Occurrence of a New Species of Phyllopora in the 
Permian Limestones.” By George W. Shrubsole, Esq., F.G.S. 
The specimen on which this species is founded is mentioned in an 
early paper by Prof. Sedgwick on the Magnesian Limestone. It was 
afterwards named Fenestella ramosa by Prof. Phillips, and considered 
by Prof. King identical with Thammiscus dubius. But with neither 
of these genera has it any relationship, as it really belongs to King’s 
genus Phyllopora, founded to include certain Polyzoa formerly referred 
to Retepora, a modern genus whose characteristics cannot be detected 
among the remains of the Paleozoic Polyzoa. The author described 
the characters of the species, and traced the history of the genus, 
which, in its range from Lower Silurian to Permian times, is cha- 
racterized by two distinct types of species. 
May 10, 1882.—J. W. Hulke, Esq., F.R.S., 
President, in the Chair. 
The following communications were read :— 
1. “On the Relations of iMybocrinus, Baerocrinus, and Hybo- 
cystites.” By P. Herbert Carpenter, Esq., M.A. Communicated by 
Prof. P. Martin Duncan, M.B., F.R.S., V.P.G.S. 
The author discussed the relations of Apiocrinus dipentas, Leucht., 
and of Baerocrinus Ungerni, Volborth, both from the Lower Silurian 
of Russia, to //ybocrinus, Billings, of the American Trenton lime- 
stone. 
Ap. dipentas was regarded as a true Hybocrinus, as it was by 
Volborth and Schmidt; but the author followed Volborth and Gre- 
wingk in considering Baerocrinus a distinct generic type. The 
calyx consists of five basals supporting five radials, of which 
only three bear arms, while there is no indication of any anal sys- 
