GLEANINGS—REPORTS. 163 
Tar Acre or THE Harra.—Mr. A. J. Richardson recently read a 
paper on this subject before the members of the Northampton Natural 
History Society, in which he dealt with the various theories which have 
been propounded, giving in detail the geological, biological, and physical 
estimates of the antiquity of the earth, and the methods by which the 
calculations were made. The discrepancies were stated as very wide, 
the physicists arguing that from sixty to eighty millions of years was 
the most that could be deduced from physical reasoning, whilst the 
biologists were of opinion that not less than 200 millions were sufficient to 
account for the vast quantity of species present on the globe, the geologists, 
however, being satisfied with an intermediate demand of somewhere 
about 120 millions. The theories of Croll’s glacial epochs and many 
other very interesting points were fully explained, and in such a manner 
as to keep the attention of the meeting with the lecturer through the hard 
facts and mathematical formula which necessarily had to be quoted. 
Aeports of Societies. 
BIRMINGHAM NATURAL HISTORY AND MICROSCOPICAL 
SOCIETY.—Gronocican Sxrcrron.—April 22nd. Mr. C. T. Parsons sent a 
curious monstrosity in the flower of a fuchsia.—Mr. H. EH. Forrest exhibited 
Cladophora cegagropila, a remarkable alga, which grows in large balls at the 
bottom of afew English lakes. It is supposed to acquire its globular form from 
being rolled about by currents at the bottom of the lake.—Mr. J. H. Lloyd gave 
an account of the rocks of the Lizard district, illustrated by a map and a large 
number of specimens.—Mr. S. Allport shewed some sections of the same rocks. 
Generat Meetine.—April 29th. Mr. Thos. Bolton exhibited in the microscope 
an elver, or young eel, shewing the whole internal organisation with great clear- 
ness.—Mr. T. Roberts exhibited spawn of the toad—Mr. J. Levick exhibited a 
double flower of the garden anemone, and in the microscope—tadpole of frog, 
showing the circulation of the blood in the gills, and the action of the cilia which 
clothe them externally on the surrounding water.—Mr. J. E. Bagnall exhibited 
valves of Pellia epiphylla, and endothecium of crocus, to shew the fibro-cellular 
tissue ; Mniwm subglobosum, a moss from near Shirley ; and Cardamine pratensis 
shewing prolification of the leaves, sent by Mr. J. Price, M.A., of Chester. 
May 6th.—GernreraL Mrrrine.—Mr. R. M. Lloyd exhibited Suecinea virescens, 
a very rare mollusc, found by himself at Acocks Green.—Mr. T. Bolton exhibited 
spawn of Perch, (?,) showing curious radial strive in the albumen.—Mr. J. EH. 
Bagnall exhibited Peziza trechispora, a micro-fungus, from canal bank, Wilne- 
cote, and Viola hirta, from Wooton Wawen.—Mr. W. H. Wilkinson exhibited a 
number of mosses from the Malvern Hills, comprising, among others, male and 
female plants of Polytrichum piliferum and juniperinum ; also Marchantia 
conica.—Mr. H. E. Forrest exhibited and read some notes upon a living specimen 
of Hydractinia echinata, which had lived in a small marine aquarium, belonging 
to Mr. A. E. Bayliss, for six weeks. He described the alimentary, male, and 
female polypites, and the two kinds of defensive zooids, and pointed out the 
remarkable specialisation exhibited by them, no one polypite fulfilling two 
functions. He also called attention to the curious relationship existing between 
the Hydractinia and the Hermit Crab, the two being always found in 
company. This specimen was an example of a triple comensalism, the shell 
being occupied not only by the crab and the hydrozoon, but also by a 
species of Nereis. Mr. W. R. Hughes said that the bond which united 
them was probably one of mutual advantage; since both the Hydractinia 
and the Nereis would profit by the crumbs dropped by the hermit crab.— 
Brotocican Srction.—May 13th. Mr. T. Bolton brought for exhibition the very 
rare thecated rotifer, Welicerta tyro, which he had recently foundin a new habitat. 
Mr. Forrest read a paper by Mr. W. A. Lloyd, the curator of the Aquarium now in 
course of construction at Aston, and formerly for many years of that at 
Sydenham, ‘‘On the Principles of Aquaria.” After reviewing the history of 
the earlier attempts to keep marine animals in confinement and the gradual 
development of the art of aquarium management, the author gave a highiy 
