23 
times, but just like.all plankton in much smaller quantity where the water was 
shallow or filled with Zostera, and where therefore there was but little current 
and flow of water. 
28th July: Of 39 oysters from Sallingsund and neighbourhood 2 had 
white and 2 blue spat. 
3rd July: Very few oyster spat in the plankton at Sallingsund, but many 
in Nykjøbing Harbour. The currents are obviously carrying the spat some distance 
round the fjord. The water from the North Sea certainly contains very few of 
the spat. A few days later there was no oyster spat even in Sallingsund. 
On the 8th—1lth July oysters from various places in Sallingsund and 
neigbourhood were examined. Of 5 from Skælholmen 1 had blue and 1 white 
spat; of 16 south of Glyngøre 1 had blue spat. Of 144 pole-dredged in Faarup 
Vig (see Table I No. 6) only 4 had spat, none of which were quite blue; of 18 
from 3—4 fathoms at Sallingsund only 1 had blue spat; of 61 pole-dredged at 
Studeholmene at Højriis none had spat, but small oysters down to 2!/, inches 
had spermatozoa with tail. Of 86 standard oysters and 150 under-sized from 
Trehuse at Salling (see Table I No. 8) 16 had spat, a »dwarf« of 2'/, inches had 
white spat; otherwise the oysters here seem but seldom to have spat before they 
are 23/, inches long. 
12th July: some oyster spat still in the water, even in days of windy and 
rainy weather, but still more of the other molluse larvæ. 
16th July: the temperature of the water has now sunk to 15? C. during 
a long period of westerly storms and rain, and the oyster spat is very scarce in 
the Sound; none at all are present in the harhour and few gastropod and mussel larvæ. 
18th—19th July: warm weather again, and oyster spat appeared 
at once. 
25th July: at Bjørndrup 74 standard oysters and 302 under-sized and 
young were dredged (see Table I No. 9), but only 6 had spat. 
On the 26th and 27th July oysters were examined in large numbers from 
Brevig and Snaven at Salling (see Table I No. 2), but only 7 and 9 respectively 
were found to have spat. 
On the 3ist of July and I1st of August oysters were brought up by diving 
in Livø Bredning (see Table I No. 11, 12 and 13), but only 3 im all had spat. 
On the 3rd of August the oyster spat were observed on the collectors: 
some were even 13 mm. The fixing of further spat on the collectors has not been 
observed later. 
In August the stock of oysters on the banks in Venø Bugt, at Oddesund, 
in Nissum-Bredning and in Sallingsund was examined (see Table Nos. 17, 15, 14, 
19, 20, 16), but spat was found in hut very few. In agreement with this the 
number of oyster spat taken in the plankton fell off in the course of the month. 
The last oysters I found with spat were observed on 24th August (1895); 
but oyster dealers in Nykjøbing informed me that they had found a few even in 
September; and the spat was found in the plankton even on September Sth. 
Whether these stragglers are able to develop must certainly be considered as 
doubtful: the temperature in the water was only 13—17? and fell very quickly 
in the following days. I had thought beforehand that July or August would be 
i 
