BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 24. AFD: IV: Ni0'8U 19 
30 2, varying between this and 53,4 2, which latter is the 
largest proportion found in any specimen of C. gobio. On 
the other hand, in 8 specimens of C. poecilopus this measure- 
ment was less than 53,+ 4, sinking to 50 (in one even to 
45,5 26). 
Difference in roughness of skin. 
Professor Smitt says in his description of C. gobio that 
we sometimes find in this species but still more commonly 
in C. poecilopus the part of the sides which is covered by 
the pectoral fins studded with small spinous formations. In 
all the specimens of C. poecilopus, young and adult, which I 
examined I found behind the insertion of the pectoral fins a 
space of small spinous points, directed backwards, which were 
usually very perceptible to the eye but sometimes could only 
be detected by the touch. Professor LILLJEBORG states that 
as a rule they exist in C. gobio as well. Of all the speci- 
mens of C. gobio examined by me only three (middle-sized 
ones) had fairly distinct rough points and as a rule the skin 
of C. gobio seems to be perfectly smooth, even behind the in- 
sertion of the pectoral fins. NILSSON, however, points out 
that in some specimens of C. gobio which he received from 
Alsace there were small spinous formations, and DaAYr states 
that on the upper half of the body the skin is sometimes 
studded with little rough points. Thus no distinguishing 
character is established in this respect. 
Comparison between the various measurements 
in the two forms. 
In my examination I have usually compared the different 
parts of the body with the whole length of the body, which 
we may probably suppose to correspond with the age. Some 
measurements I have taken in other proportions, as, for ex- 
ample, the length of the base of the anal fin in proportion 
to its distance from the tip of the snout; the length of the 
