WIE 
Conclusions. 
The Libraries from which I borrowed the greater part of the 
works treating of the subject were: 
The Royal Library at the Hague, 
The Library of the Leiden University , 
The Library of the Utrecht University, 
The Library of the Groningen University , 
The Library of the Amsterdam University , 
The Library of the Royal University at Gottingen, 
The Library of the Royal Zoological Society “Natura Artis Ma- 
gistra’”’ at Amsterdam , 
The Library of the Royal Academy of Sciences at Amsterdam , 
The Library of the Museum of Natural History at Leiden, 
The Library of the Dutch Zoological Society at den Helder, and 
The Library of the Dutch Entomological Society at Leiden. 
In the part headed Literature on the Subject 1 have given an 
idea of the mass of works and articles written about it. I here 
present to my readers a list of the different appearances found by 
me in the works which I have consulted. Of each appearance | 
have noted down as far as possible, the date, the locality and the 
names of the observers. The numbers correspond with those in the 
4th. Chapter. 
1. — 1522. — Near the Isle of Moos, Norway. 
2. — 1640. — Most probably in the Sound between Sweden and 
Denmark. — Burgomaster of Malmo. 
3. — 1687. — Damsfjord in Norway. — Several persons, and at 
one time eleven persons together. 
