24 
the main spawning time of the oyster, and the investigation of this point was 
therefore neglected somewhat in the beginning; hut from the data we may believe 
that it begins a little earlier. It was also some time before I found out that we 
could fish the small spat in the open with sufficiently fine pelagic net of miller's 
gauze. Unless the period during which the spat remain wlthin the cavity of the 
mother-animal is very short, it seems as if a relatively small number of oysters 
take part yearly in reproduction; to determine the duration of this period is obvi- 
ously an exceedingly difficult matter owing to the complete closure and lack of 
transparency of the animal and nothing appreciable is known regarding it. 
Although the weather in 1895 was scarcely favourable to the well-being 
of the oysters in the Lim Fjord, there was nevertheless as shown a considerable 
quantity of spat in the fjord, and the fixed spat was also observed both on my 
collectors and on other objects in the fjord: posts, boats etc.; but what surprised 
me most in these investigations of 1895 was, that I could not with certainty find 
the young of the year in quantity on the banks after the spawning time, e.g. in 
October. In Thisted Harbour I saw boats quite densely covered with the spat of 
the year; but on the Lysen (Brevig) banks (see Table I No. 3) I found no spat 
in October. 
On Table II No. 13 the size of the spat on August 8th 1895 is represented 
from measurements of 24 specimens taken on the collectors; No. 14 shows the 
size of the same spat on September 24th 1895; a few are even already over 1 
inch in length. If we remember that growth continues even somewhat late into 
the autumn but stops in winter, we should clearly find each spring a group of 
