580 LÖNNBERG, OBSERVATIONS ON CERTAIN FLAT-FISHES. 



äppearance several characteristics both of the plaice and of tlie 

 flounder. It has the frontal ridge quite conspicuous but the 

 anterior part of it is exactly similar to that of the flounder; it 

 is sharp or rough with numerous small tubercles. The posterior 

 part is in the plaice divided into larger protuberances, in this 

 speciraen two, corresponding to the two hindmost ones of the 

 plaice. The head on the eyeside is rough with strongly "ciliated" 

 scales and small spinous warts which are smaller than in the 

 flounder but are rather doser together. The coloured side has 

 nearly all the scales of the caudal peduncle strongly ciliated; 

 near the lateral line too, very many ciliated scales are scat- 

 tered all along this side. Even along the base of the dorsal 

 and anal fin we see the spinous warts, which are characteristic 

 for the flounder, hut they are smaller in this form. On the 

 blind side we find ciliated scales only on the breast, but the 

 scales round the lateral line are enlarged and are closer to- 

 gether so that they are a little imbricated; thus they do not 

 feel so smooth. 



The colour of this specialen is exactly that of the flounder, 

 without red or yellow spöts. The blind side has a few small 

 brown spöts scattered on its surface, also reminding more of the 

 flounder. The flounder has, namely, very often, or in most cases, 

 just such small brown spöts on the blind side, but if the plaice 

 is coloured at all on the blind side, there is usually a large 

 region of the body, beginning from the tail or from the head, 

 that is coloured. The outer äppearance of this form thus nearly 

 approaches that of a flounder. The uumber (74) of rays in the 

 dorsal fin on the contrary, is so large that it nearly equals the 

 maximum number (76) of rays in the dorsal of the plaice, and 

 far exceeds the same of the flounder (62). The number of rays 

 in the anal fin however is for this form only 49, — thus lower 

 than the minimum for the plaice (52, nornially 55), but higher 

 than the maximum for the flounder (42) therefore it is inter- 

 mediate in character. The relative measurements taken from 

 the above given table show some interesting facts if they be 





