28 THE AQUARIUM A8 A FIELD OF MICROSCOPICAL RESEARCH. 



Chitons deposit their eggs closely united in clusters, each egg pre- 

 senting a curious appearance from the -folds of transparent mem- 

 brane, which, gathered up in branches at different points on its 

 exterior, give it the appearance of a statoblast. The young have no 

 shell when first hatched, but their backs are marked with seven 

 furrows, between which close granules indicate the future shelly 

 structure. I have placed upon the table, among other microscopic 

 slides illustrating the minute life of my Aquarium, some of these 

 eggs mounted in sea water. The shells that are sometimes dredged 

 up from a good depth at sea will be found most prolific in develop- 

 ing forms of animal life, and some kindly sent me from Wey- 

 mouth bore several specimens of Grantia compressa in a living 

 state, but unfortunately sponges do not live long in a tank, nor 

 are they desirable tenants, they exhaust the water very quickly, 

 and then dying, poison it. This is to be regretted, for much has 

 yet to be learned in reference to them, especially about their 

 reproduction. Some sections of a Grantia are on the table. 

 Various forms of Tunicata are found attached to these shells, and 

 to sea weed. Many of you may remember some Perophora I have 

 exhibited on our gossip nights, which were brought from the 

 Aquarium, where it grew and budded for months. The growth of 

 Bowerbankia, Syncoryna, and other Polyzoa, may be readily 

 observed and noted by this additional aid to microscopic research, 

 and I should, I fear, sadly try your patience if I detained you 

 while I enumerated the many forms of marine life I have had 

 brought thus before me, but which, alas ! I have been too lazy to 

 profitably use as I ought; but if I can by these few suggestions 

 stimulate any amongst you to adopt this line of observation, I can 

 promise you that your pleasure shall not be satiated, but that fresh 

 stores of interest will be continually opening to your gaze. 



