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oysters, the shells still hanging together, probably the young of 1894; many spe- 
cimens even were still living. I am unable to say definitely whether it was the 
case hut I believe that the frost had killed them. Many authors state in the 
literature on the oyster that the enemies of the oyster thin out the stock so much 
and it is certain that the boring snails and worms as also the boring sponges 
are very destructive; but of these we have only the last-named in the Lim Fjord, 
and they had not been the cause of death,as where they have been they leave 
some easily recognisable sign. I have found it very difficult on the whole, in 
spite of careful search, to detect the animals or plants which directly attack the 
oysters when fixed; in fact, apart from the boring sponges, worms (Polydora) and 
man, I have been quite unable to find any with certainty; on the other hand I 
have seen a Gammarid building its tubes of mud-particles over the shells of the 
young oysters and the whole of the stone on which they had fixed themselves in 
the well on board, and almost completely covered the oyster shells with these 
tubes. As every storm in the Lim Fjord stirs up the loose layers of the hottom 
a great deal, so that the water becomes hrown with the deposited mud-particles, 
these Gammarids will always be able to find sufficient materials even if the oysters 
are fixed high above the bottom; and if the tubes are only a little advanced the 
mud-particles will be able to adhere of themselves, and the oysters will therefore 
soon be covered by quite a layer of mud. This must be a great hindrance to 
" their growth and may at length indeed smother them completely. That the 
starfishes (Asterias rubens) eat oysters I have never been able to determine, in 
spite of eager search on the banks where there were both oysters and starfishes; 
it would require a large starfish in any case to eat an ordinary well-developed 
oyster; that they feed upon other molluses on the other hand I have often seen, 
but always only those which they could quite surround and smother. It is also 
undoubtedly right that starfishes may be able to feed upon smaller oysters; we 
have direct observations on this point from Schiemenz. 
There are a few species of animals in the Lim Fjord, some gastropods 
(Acmæa testudinalis and Chitons), which are very fond of gnawing at the upturned 
shell of the oyster; they do not penetrate very deep as a rule, so that they can 
scarcely cause any real damage to the oyster; they might even be considered as 
doing some good, as they therewith keep the upper shell clean from plant growths. 
These gastropods appear especially on hard ground; without them such plants as 
Fucus, violin-strings (Chorda) and the like, would certainly overgrow the oysters 
completely and possibly move them away from their place. These small gastropods 
thus play an important part in the Lim Fjord, which must be more closely inves- 
tigated in the future. I have only wished to draw attention to the matter here. 
Possibly they destroy the very small, fixed spat. 
The greatest dangers to the development of the oysters certainly do not 
come from the animal life in the Lim Fjord, but much more from the surroun- 
ding natural conditions and vegetation. The cold and especially the ice 
have already been mentioned; the latter are certainly to blame that the oysters 
are not found in quite shallow water in the fjord, but what obviously destroys 
most oysters is the mud or sand, as also at places the disturbance caused by 
the waves during storms. Ås regards the first two I have personally not seen 
