SCIENTIFIC SUMMARY. 
203 
Mr. Carter maintains that the structure of the spherical coats is identical 
with that of the Hydractinise, and that the central chambered core is probably 
-a Foraminifer on which the first incrusting growth of the Parkeria took 
place. Loftusia , a singular melon-shaped fossil from the Nummulitic 
formation of Persia, closely resembles Parkeria in general characters, and if 
the latter is to be transferred to the Hydrozoa, Loftusia must go with it ,* 
and Mr. Carter considers that with the assistance of a new' form which he 
describes here under the name of Bradya tergestina from the Lower Chalk, 
the early palaeozoic Stromatoporce, the position of which has always been 
doubtful, may be brought under the same category. 
Supposed Badiolaria in Carboniferous Limestones. — According to a report 
in u Nature,” March, 22, 1877, Mr. J. D. Siddall has discovered remains of 
Radiolarians in the Halkin and Minera limestones. Some polished blocks of 
these limestones are said to show specimens of Radiolaria, beautifully pre- 
served, and representing most of the types to be seen in the Barbadoes 
earth. The identification of these objects is, however, we believe still 
doubtful. 
A New Fossil Sponge . — Mr. W. J. Sollas has described before the Geo- 
logical Society a very interesting fossil sponge from the Cambridge Coprolite 
beds. He regards it as belonging to the group named Holorhaphidota by 
Mr. Carter, in which the skeleton consists entirely of siliceous spicules, 
united to form fibres, and describes it as characterized by the possession of 
an irregularly reticulate fibrous skeleton of this kind, composed of acerate 
spicules lying parallel to each other and to the sides of the fibre. Although 
these spicules are still sufficiently well preserved to be figured and measured 
individually, and the author is of opinion from the structure of the sponge 
that they were originally siliceous, they now consist of calcareous material. 
He indicates that a similar replacement has occurred in the case of various 
sponges of the genera Manon and Porospongia ; and that this fact is of much 
interest as getting rid of the necessity of establishing for these forms a 
peculiar order of Calcispongiae, composed exclusively of anomalous extinct 
forms resembling in structure existing siliceous types. The new fossil sponge 
is described under the name of Pharetrospongia Strahani. Some doubts are 
expressed by Fellows of the Society as to the supposed replacement of silica 
by carbonate of lime. 
METEOROLOGY. 
The Alveoliform Depressions in Meteorites . — M. Daubree notices the pecu- 
liar depressions often observed on the surface of meteorites, which have 
been compared to the impressions left by the finger upon a soft paste. Such 
impressions occur in all sorts of meteorites. It has been supposed that these 
depressions are due to a bursting process occurring at the surface of the 
meteorites when suddenly heated on entering the earth’s atmosphere, but 
none of the experiments made to test this supposition have confirmed it. 
M. Daubree says that the large, imperfectly burnt grains of gunpowder 
which often fall in front of the mouths of cannon, present alveoliform depres- 
sions perfectly similar in form to those of meteorites. From direct experi- 
