VI 



turesome, if indeed possible at all, to attempt to ar- 

 rive at any natural grouping of them. 



In this account of the collection of Leptocephal- 

 ids in the Zoological Museum at Upsala I have not 

 therefore considered it wise to do so in any degree; 

 it seemed better first to treat those forms that are 

 already known and then to .take, up the new ones 

 that I have succeeded in discovering in the collection. 

 Within, however, the bdunds of these two categories, 

 I have tried to arrange the species in such a way, 

 that those which in habit most closely correspond and 

 are in all probability nearly related to each other have 

 been placed together. I have not deemed it necess- 

 ary to give descriptions of the first category, since 

 the species here have already been described in detail. 



There is an agreable duty that yet remains for 

 me to discharge. I desire namely in this place to 

 give expression to my heartfelt gratitude to my ho- 

 noured teacher, Professor Tyoho Tullbekg, for the 

 kind interest he has shown in my zoological studies, 

 for the valuable advice and explanations' he has con- 

 stantly therein afforded me, and for the goodwill I have 

 ever been the recipient of at his hands. 



