MICROSCOPICAL AND NATURAL HISTORY SECTION. 
April 13th, 1874. 
Professor W. C. Williamson, F.R.S., &c., President of the 
Section, in the Chair. 
Mr. Plant, F.G.S., exhibited some bones of the extinct 
Auroch {Bison ijtIsgus), which had been taken from a deep 
fissure in the limestone above Castleton, where nearly the 
whole of the skeleton had been found, together with the 
bones of the reindeer. 
Mr. Thos. Kogers read a paper “ On the Introduction of 
Planorbis dilatatus ” (Gould), a North American fresh water 
mollusk, which he discovered (June, 1869) adhering to the 
stones immediately below the surface of the water in the 
Bolton canal at Pendleton, and in close proximity to the 
blowing room refuse discharge, and warm water discharge 
from the engines of Messrs. Armitage’s cotton mill. He also 
afterwards found the same species under similar conditions 
in the canal adjoining the mills of Messrs. Hylands, at 
Gorton. After examining all the circumstances under which 
the mollusk was found (the details of which he placed before 
the members of the section), he was led to believe that its 
introduction into this country was by means of American 
cotton, which had been used for such like war purposes as 
barricades for steamboats or river defences by the soldiers 
in the civil war during the presidency of Abraham Lincoln, 
and which had been accidentally submerged in water and 
redried with the fry or spawn masses of the Planorbis 
attached to its fibres previous to its exportation to England, 
and this ultimately finding its way through the cotton 
refuse into the canals adjoining the aforementioned mills, 
