117 
February 24th, 1873. 
Joseph Sidebotham, F.R.A.S., in the Chair. 
Mr. Hardy made a communication to the Section respect- 
ing the occurrence of one of the few large bivalve mollusca 
within the limits of the Manchester district, the species 
in question, Unio tumidus of authors, having been observed 
in considerable numbers in the canal at Barton, a little 
beyond the aqueduct, and in several places between there 
and Stretford : a few dead shells were also found in the 
river. 
References were given to works on local conchology in 
which no notice of this shell as an inhabitant of the district 
was to be found. Allusion was also made to the record of 
a single living example of another species of the same genus, 
the U. pictorum of Linne, in the canal near Romiley ; and 
during the conversation which followed the reading of the 
paper Mr. T. S. Peace announced that this latter shell had 
since been collected in quantity in the same canal some 
short distance beyond Marple; thus establishing satisfac- 
torily the occurrence of two out of the three British species 
of Unio, the third not being at all likely to inhabit any of 
our rivers in their present condition ; although the speci- 
mens collected at Barton were many of them much larger 
than others of the same species collected in more southern 
and apparently more favourable localities, and exhibited to 
the meeting. 
Joseph Sidebotham, F.R.A.S., exhibited an old micro- 
scope sent by Mr. Rideout, and explained its construction. 
The workmanship of the brass-work was very beautiful, 
and the various motions and appliances much admired ; he 
also read a letter from Mr. Dancer, who for several reasons 
