THE AQUARIUM. 65 
part of a glittering Dragon-fly became plainly visible ; 
very quickly the whole insect emerged from the 
blackened shell, spreading its great gossamer wings 
to the sun, which was shining brightly through the 
window. 
“T had by an accident, for I can hardly call it the 
result of a course of observation, witnessed one of 
the most extraordinary and complete of the meta- 
morphoses that occur in the whole range of insect 
life, and was all anxiety to pursue my discoveries. I 
was, however, baffled in all future attempts, at that 
time, to extend my knowledge of. the mysterious 
creatures of the world of waters; and it was not till 
recent discoverers have shown how the Aquarium 
may be made the means of facilitating studies of that 
class, combined with an elegant and delightful mode 
of amusement, that I resumed the course of observa- 
tion which has been so long interrupted by difficulties 
which appeared insurmountable.” 
Those plants which naturally grow entirely below 
the surface of the water, are best calculated for the 
purpose of the Aquarium, as they are less liable to 
decay ; and their leaves being mostly very fine and 
delicate, they not only present a more beautiful ap- 
pearance, but the breathing organs are more gene- 
rally distributed throughout the water. This is par- 
ticularly noticeable in marine plants, they consisting 
frequently of bunches of delicately formed filaments, 
of so fragile a texture as to be very easily broken, 
but which float at their ease upon the ocean, waving 
is E 
