BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 24. AFD. IV. N:0 3. ö 
F. A. Smitt that I have gone into this subject. For this 
purpose, I have employed the same method of examination 
as Professor SMITtT has done in his »Kritisk förteckning öfver 
de i RBiksmuseum befintliga salmonider». K. V. Akad. Handl. 
Band 21. In measuring in his manner as many specimens as 
possible of different ages and of both sexes, one gets an in- 
sight into the development of the two forms and also of 
their relations. 
I take this opportunity to express my sincere gratitude 
to Professor SMIitT, who has furnished me with the means of 
familiarizing myself with his method of working and also 
given me a great deal of valuable advice and explanation. 
As" material for the examination, Professor SMITtTt has 
kindly placed at my disposal the collection of specimens of 
both forms in the Royal Museum. For some supplementary 
investigations many specimens from the Universities of Up- 
sala, Lund, and Stockholm and from »Högre Allmänna Läro- 
verket» in Gefle were lent to me, for which I am very much 
indebted to Professors T. TuLLrBErG, A. W. QUENNERSTEDT, 
W-. LECcHE, and Lektor W. ARNELL. 
My material has thus been very rich. Also the specimens 
examined were taken from many different places in Swe- 
den (one specimen of each of the two forms I received from 
Denmark). I have, following Professor SMmITT's method, com- 
pletely measured 68 specimens of C: gobio, 34 of each sex, 
and 51 examples of OC. poecilopus, 30 males and 21 females, 
besides which I have had at my disposal a great number of 
C. gobio and a few of OC. poecilopus to use as tests if ne- 
Cessary. 
First I have revised the characters, by which the va- 
rious authors have distinguished the two species, after which 
I have discussed the other points of similarity and dis- 
similarity which my examination showed to exist and the 
consequences of these. The result of my examination shows 
that in their development the two forms follow almost the 
same course and that the differences between them are not 
great enough nor sufficiently constant to give us a right to 
pronounce them two distinct species. 
