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. 



" I 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 

 6* E 



