98 ESMARK : MOLLUSCA OF NORWAY. 



The most common of our new species is Pisidiuni lilljeborgi. 

 I found it first at Tdnset, which seems to be its southern Umit, 

 towards the north it goes right up to the most northerly frontier 

 of our country. Pisidium hoyeri is limited to Tromso Amt. 

 Anodonta is as yet very little' known. It is certainly not rarely 

 found, but has hitherto been very little, investigated perhaps 

 the least of all our mollusks. 



Margaritana margaritifera is common from Lindesnass to 

 Nordkap. Dr. Erik Pontoppidan in his ' Det forste Forsog paa 

 Norges naturlige Historie,' 1752, speaks of Maig. maigaritifei-a 

 because they were known and fished on account of the pearls 

 contained in them. As long as Norway was united with Denmark, 

 the Queen had the exclusive privilege to fish and collect the 

 pearls in many rivers in the diocese of Christiansand. Some 

 of them must have been handsome, and a great number have 

 also been collected, as in the possession of the Danish Royal 

 family, are found ornaments exclusively set with Norwegian 

 pearls. From the year 18 14 when Norway was separated from 

 Denmark, this privilege also ceased, and the pearl fishing may 

 now be carried on by anyone. The right belongs, consequently, 

 now solely to the proprietor of the ground where the pearl 

 mussel is found. Very few, however, make use of this right, 

 and still fewer understand the fishing or the value of the pearls ; 

 which, besides, are not everywhere of the same beauty. The 

 pearls are now fished chiefly by gipsies and stragglers, who, 

 however, proceed in such a way as completely to ruin the pearl- 

 mussel. The colour of pearls in the diocese of Christiansand 

 I have not seen. In the county of Jarlsberg they are found in 

 almost all the rivers ; I have had occasion to see about three 

 hundred and thirty pearls belonging to the Count Wedel- 

 Jarlsberg. The colour and lustre are in moSt of them whitish 

 or bluish white, some have a reddish lustre, others are dark 

 olive-green, liver-coloured, and grayish-brown. Their forms 

 are varying, most are spherical, but also oblong, and monstrosities. 

 The greatest white pearl is oblong, the diam. is 8 "6 mill, and 



J.C, v., Oct-, 1886. 



