NATURAL HISTORY. 41 
them into four genera, viz. the Notonecta 
(proper), Plea, Sigara, and Corixa, which it 
would be out of place, in a work devoted to 
the microscope, more than to name. His 
paper, which displays much erudite knowledge 
of systematic arrangement, may be consulted 
in the twelfth volume of the Transactions of 
the Linnean Society. 
