233 



respect to the third character that the caudal fin should be 

 «rounded» in С quadricornis^ and «truncated with rather sharp 

 corners» in C. hexacornis. this does not hold good with regard 

 to C. quadricornis. In the specimens before me from the Baltic, 

 the upper and, or, lower rays reach farthest when the caudal 

 fin is folded together, and when it is distended it is truncate, or 

 at any rate only very slightly rounded, the upper corner generally 

 pointed, the lower rounded; this also agrees with Lilljeb org's 

 description: «The caudal fin which is cut off straightly, or flatly 

 curved, sometimes with pointed, sometimes with rounded 

 corners» M- There is also some variation in the East-Greenland 

 specimens, as the caudal fin generally is slightly rounded''^), 

 but often very insignificantly so, nay in one specimen it is even 

 truncate. The posterior margin of the caudal fin is thus subject 

 to an individual variation with regard to contour, and cannot 

 consequently be employed as specific character. 



It will hereof be seen that the American «C hexacornis'» 

 cannot be distinguished from the European С quadricornis by 

 the characters which Jordan and Ever mann state, and 

 about whose value they are themselves doubtful. 



In the subjoint table fp. 234) I give a survey of some meas- 

 urements of the 16 specimens in question from East-Greenland, 

 partly for use for further comparison with Fourhorned Cottus 

 of other seas, partly for the elucidation of the more important 

 differences with regard to sex and age. 



The relative length of the head, the upper and lower jaw, 

 the distance of the first dorsal fin from the end of the snout, 

 the distance between the dorsal fins and the length along the 



1. с p. 147. 



In one 236 mm. long male, we see the peculiar circumstance that the 

 posterior margin of the caudal fin is sinuate, the middle ray is the 

 longest, two rays above and underneath it are somewhat shorter, the 

 two rays at each corner again are a little longer than these. 



