March, 1888.] elliott society. 199 



breathe or the power to free itself of the mud, and consequently died from 

 want of oxygen and food. 



I should mention here that these ponds have mud bottoms, very soft, a per- 

 fect ooze in fact, which contains a low organic plant somewhat like a sea weed 

 whose fibres rjass through it in a perfect nstw^ork, like a connective tissue, to 

 a depth of several feet. This fibre supports the oyster, but not entirely, as I 

 will show below. 



It is impossible for a bay oyster to live in this mud, its own weight will carry 

 it below its surface, it csnnot then obtain ozygen or food and dies. Being sat- 

 isfied on this point, the question arose in my mind : why was not the native 

 Pond Oyster smothered also ? and it was only by close study of its habits, and 

 comparison of its anatomy, that I have been able to understand its peculiar life. 



Looking at tLe beds of these Pond Oysters, one v,'Guld scarcely have thought, 

 unless familiar with its habits, that they contained oysters. The oyster gath- 

 erers knew where to look for them by a small hole or depression of the surface 

 of the mud. At the centre of this depression, just under the surface, the 

 Oyster was found, invariably in a perpendicular position, and partially covered 

 by a frill of green sea-weed, which always grev/ over and completely covered 

 all of the shell v/hich was not encased in the mud. 



Beheving that the Pond Oysters had some power of preventing the mud from 

 closing over them, I filled several of these depressions with an inch or two of 

 mud, just above the oyster, which was about a foot below the surface. Very 

 soon after I noticed a jet of water burst through the mud with force enough to 

 scatter it ; this perfci-mance was repeated several times in quick succession 

 and continued every few minutes until the oyster had completely cleared away 

 the mud above it. Each oyster which I covered did this in the same manner, 

 apparently by opening the shell and closing it suddenly. I took a bay oyster 

 and a pond oyster, and placed them side by side in the mud, about two inches 

 below the surface, and on viciting them the next day I found that the pond 

 oyster had cleared itself of the mud above, but the bay or river oyster was still 

 covered. Thinking that perhaps if placed in the mud with a little assistance, it 

 might soon learn this art of clearing itself, I placed a bay oyster between two 

 pond oysters which, in clearing themselves, would keep it clear also. A month 

 later I took it out and it w^as dead, with every appearance of having been 

 smothered. This leads me to believe that the bay oyster not only lacks the 

 power of clearing itself of the mud, bat is also unable to reach the oxygen in 

 the mud, for if kept above the mini it fattens ami grows excellently. With the 

 knowledge gained in these experhnents, I have since been able to work out the 

 cause of the disappearance of this excellent bivalve from our ponds, and also to 

 note some of its unusual developments. 



The spawning season of the oyster in this latitude, is usually, with slight va- 

 riations according to conditions, from the middle of March to the middle of 

 August. During this time the ova are found floating about in the bays and 

 rivers. They float tmtil they reach a certain stage of development and then 

 sink to the bottom. The ova of the pond oyster are usually confined to the 



