/IQS .MONOCULUS. 
brown above, and reddish beneath. We are in- 
formed in vol. 40 of the Philosophical Transac- 
tions that this insect has been found in great 
plenty in a pond on Bexley Common in Kent. It 
is also added, that the same pond, having been 
perfectly dried, and being suddenly fdled during 
a heavy thunder-storm, swarms of the same ani- 
mal were again observed in it within the space of 
two days after. 
ISIonociilus Piikd\ called, from its peculiar start- 
ing or springing motion, the Water-Flea, is an 
almost universal inhabitant of stagnant waters, 
appearing sometimes in such vast swarms as to 
cause an apparent discoloration of the water 
itself. It is an insect of a highly singular and ele- 
gant appearance, exhibiting, when magnified, a 
beautiful distribution of internal organs. Its gene- 
ral length is about the tenth of an inch, but it is 
sometimes seen considerably larger: its shape is 
oval, somewhat truncated in front, and sharply 
pointed behind: the body is inclosed in a bivalve, 
transparent shell, which when examined by the 
microscope appears finely reticulated: on each 
side the head is a strong transparent jointed arm, 
forking into two divisions, and terminating in 
several setaceous branches: the tail which is ge- 
nerally inclosed within the shell, is occasionally 
protruded in the form of a strong curved and point- 
ed process: the eyes of this animal are of a singu- 
lar construction; they are large in ])roportion to 
the insect, placed very near each other, and ap- 
pear to consist of many separate globules, of a 
