[3] PRODUCTION OF OYSTERS IN A NATURAL BASIN. 1039 
their food and afterwards secreted in connection with the calcareous 
matter of which the shells are formed. 
Besides the part which the conferva plays with regard to the tempera: 
ture and oxygenation of the water, it probably furnishes the chief food 
of the oyster in the enormous masses of spores which it gives off. A 
similar but less important role as a means of nourishment is taken by 
the young of Medusa aurita, which occurs in the lake in enormous quanti- 
ties and of all sizes. The young of the species of mollusks mentioned 
and of the crustacea living in the lake are less important in this respect. 
A little Gammarid, probably a variety of G. pulex, and the common 
shrimp, Palemon squilla L., notably the last named, are exceedingly 
numerous. 
The peculiarities above communicated with regard to the plant and 
animal life of this remarkable basin I did not of course discover dur- 
ing my first short visit, but the existence of a greater quantity of oysters 
than I had heretofore seen collected in one place, combined with the 
discovery of the branches of the dog rose covered with young oysters and 
the peculiar situation of the lake, were sufficient facts to warrant me, 
after my return to Stavanger, in advising my acquaintances living there 
to form a joint stock company, as soon as they could agree with the three 
owners of the lake as to the terms of the lease, to carry on oyster culture 
with combined forces, and I promised to support such an association in 
this matter by word and deed. A sufficient number of share-holders in 
such a company was quickly found, and they intrusted to the well-known 
customs-officer H. Gundersen the task of negotiating with the owners 
of the lake and agreeing with them about the terms of the lease. When 
this business was settled fourteen experimental collectors were set out by 
Gunéersen on the 31st of July. These experimental collectors consisted 
partly of willow twigs fastened with nails to a wooden frame of laths, 
and partly of boards covered with cement. By means of stones fastened 
with ropes to the lower ends of the collectors these were held under the 
surface of the water in a vertical position. On the 17th of October, 
these were examined by some members of the company, among them the 
young pharmacist Buch, curator of the Stavanger Museum, and school 
principal A. Olsen, both of whom had been my companions in the examina- 
tion of Oyster Lake. Mr. Buch communicated to me the result of this 
preliminary trial, which was certainly surprising because of the rapid 
growth of the oysters deposited—to particularize, some examples in the 
course of two months and seventeen days had reached a diameter of 35 
millimeters—and because, also, of the unexpected fact that swarms of 
young had been emitted, since they found a great quantity of attached 
young so small that they could hardly be seen by the eye alone, and so 
could not have been more than a couple of days old. 
On taking up the collectors Gundersen observed that the stones which 
were fastened to them to hold them under the water were quite warm 
to the touch, which was so much the more remarkable because cold 
