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and he thought it might be a question worth asking whether the germs 

 might have come from a common water supply. 



Mr. Parsons said the plants in this tank were sometimes changed. 



Mr. Michael said that no new plant had been put Into the Victoria Regia 

 tank for some years, but whether plants had been transferred from it was 

 of course another matter. 



The President said he had a short communication to make, which he 

 thought would be of interest, relating to the discovery by his friend Pro- 

 fessor Moseley of eyes embedded in the actual shell of a Mollusk. He had 

 himself during some investigations made 40 years ago found some peculiar 

 canals in the shells of Chitons ; he had only the dry shells to work upon, and 

 thought at the time that some organs might pass into them, but had no idea 

 as to their remarkable character. Mr. Moseley having had the opportunity 

 of examining a specimen of Chiton preserved in spirit, had made this 

 remarkable discovery. The animal was very like the common Limpet in its 

 anatomy ; but instead of having a simple conical or oblong univalve shell, it 

 had a multivalve shell. The small Chitons found on our coasts had much the 

 same kind of shell as the common woodlouse, its overlapping valves being 

 jointed so that the animal could roll itself up. It was found that in certain 

 Chitons the shells had two sets of perforations, one large and the other 

 small. The large orifices contained very perfect simple eves, of a rather 

 prolonged form; each having a calcareous cornea, behind which there was 

 a crystalline lens with an iris, and then a vitreous humor and a retina. 

 The mouths of the small passages were filled with small plugs of tissue, 

 probably constituting organs of touch ; and it was found that the nerves 

 of these eyes and the nerves of the small tactile organs came off from 

 the same plexus. These organs did not occur in all Chitons, but only in 

 those of tropical seas ; no English species had them. Their number was 

 most extraordinary, 3,000 having been counted on a single anterior valve, 

 while there were at least 8,500 eyes on the remainder. This multiplication 

 of eyes was certainly a most remarkable phenomenon, and was not a 

 little puzzling to understand. The Limpet, which, as we commonly see it, 

 remained firmly fixed to the rock on which it lived, was known to move 

 about when the tide was up, and to go in search of food, and then to come 

 back again to its place. This had been frequently observed j but how it was 

 that these creatures found their way back to the same holes again, had 

 never been satisfactorily explained. Perhaps Dr. Buckland's observations 

 on certain Snails which make hollows in limestone rocks, might apply also to 

 Limpets. He thought they secreted an acid ; and to detect this he made 

 one walk over a blue ribbon stained with litmus, and he found that in doing 

 so it left a red stain. His idea about it was that the track of acid mucus 

 which was left behind them formed the means by which they guided 

 themselves back again. But if Limpets and eyeless Chitons are thus guided, 

 it is difficult to find a use for the multiple eyes of the species that possess 

 them. The President thought it was a matter of some little historical 

 interest that 40 years ago he had detected these passages in the shell, of 

 which the use was only now found. He would illustrate the matter by 

 placing under the microscope in the room some of the shell-sections which 



