1042 REPORT OF COMMISSIONER OF FISH AND FISHERIES, [6] 
months of the year. The shoaling young retain their swimming power 
far longer than is stated by the authors who have attempted an expla- 
nation of this question. Gundersen and Prof. G. O. Sars have kept them 
living as long as eleven days, while the authors known to me state the 
duration of their swimming power to be four days at the most. 
That all the conditions for a vigorous oyster growth are present in the 
above-described basin to an extent hitherto unknown is best shown by 
the rapid growth of the oysters living therein, their fatness, and the quick 
development of their reproductive function; to give details, individuals 
of eleven months old had already emitted broods of young. With refer- 
ence to the question of the fertility of the oyster I will venture to remark 
that according to my opinion this is placed too low by many late writers 
when they estimate the number of young which an adult oyster will emit 
as only 1,000,000 or even fewer; for | am convinced that Leuwenheck 
is correct in putting the number at many millions, yes, so far as I recol- 
lect, at 9,000,000. 
From an oyster eleven months old taken from one of the collectors, 
which probably had scarcely begun to emit young, since many oi the 
embryos had not yet broken through the egg-membrane, I preserved by 
estimate half of the number of young, and I am greatly at fault if this 
number does not considerably exceed 1,000,000. 
The plan of suspending receptacles for ae young, made of birch wood, 
on telegraph wires stretched in many directions across the lake and fast- 
ened to iron bolts which are fixed in holes made just at the margin of 
the water, was carried out this year. Last year only a couple of re- 
ceptacles were placed; these were rather heavy collectors, consisting 
partly of old crab-traps and baskets filled with sticks, broken crockery, 
shells of blue mussels, Mytilus edulis L. and modiolus, were suspended on 
heavy, well-tarred ropes. Many of these ropes, however, became so 
rotten in the tepid fresh water that they parted and the collectors some- 
times sunk in water so deep that they could not be found; but the col- 
lectors which were hung up and fell down in a less depth of water were 
found to be thickly covered with vigorous young oysters. The recep- 
tacles built by Groom, the merchant, of pieces of boards joined together 
in the form of book-cases showed themselves to be next best to those 
made of birch. They were, however, covered with young only on the 
under side of the pieces. On the same area the birch collectors yielded 
a much larger result, and the young on them could be easily gathered 
without injury. The young, which are intended for shipment or to be 
placed in the fattening grounds leased by the stock company, are taken 
from the lake down to North Fjord, where they are put into boxes with 
holes bored in them until they are sent away. In the latter part of July 
65,000 young oysters averaging 24 inches in size, packed in 43 boxes, were 
transported 10 miles and deposited in a fattening-place 14 miles from 
Stavanger. Of this number less than 100 were found dead when de- 
