COMMON KLOI XJ)K1!. 



4U1 



shape as in the Plaice, and its length in our specimens us has <renerally seemed to be better developer] than 



varies between 19 and -I?) % of that of the rest of the in the other sjwicies of the genus. 



bod\'; but the numljer of the branclied rays has con- In order to account for the external relations be- 



stantly proved to be no more than 12. Vent and anal tween thf Plaice and the Flounder, and to give the 



spine as in the Plaice. The former, ho\ve\er, is com- most important changes of growth in the two species 



]jarati\ ely large, and is furnished on the eye side with a — excluding their earliest stages — we here append the 



urogenital papilla, which in the specimens examined by following table of averages: 



The internal organs of the Flounder al.so corres- 

 pond in the most essential respects to those of the 

 preceding specie.*. The liver is undivided and oblong, 

 and lies on the left side. The spleen is dark red, round 

 on one side and flat on the other, and lies by the ven- 

 tricle, close to the large, round gall-bladder. The in- 

 testine is about 1' 2 times as long as the whole fish, 

 and lies in coils, without any regular curves, of almost 

 uniform diameter, and without anv considerable dis- 

 tension. It is furnished with two very shoi*t pyloric 

 ap|)endages. The heart is long and quadrangular. The 

 milt-sacs of the male arc double and heart-shaped, and 

 lie at the extreme end of the abdominal cavitA". The 

 ovaries of the female are also double as usual, very 

 long and ])ointed; only the broad anterior end lies in 

 the abdominal cavity, the long tips being furnished, as 

 in the other Flatfishes, with special cavities, one on 

 each side of the base of the anal fin. This double 

 cavitv extends almost to the end of the anal tin. 



The coloration is highh' variable. ()n the eye 

 side it is generalh' grav or yellowish gi'av, in most 

 cases marked with round, pale orange spots, Avhich also 

 occur on the fins. The fins are of the .same colour as 

 the bodv, but somewhat lighter. The blind side is 

 white, but often spotted Avith brown, esjiecially along 

 the lateral line. In specimens where half this side is 

 broAvn, the bi'own colour always belongs to the caudal 

 part. Sometimes, though extremely seldom, the blind 

 side is entirely brown. The iris is brassy-yellow, the 

 pupil blue. Among the numerous colour-varieties of 

 this species there is one, which the Royal Mu.seura has 

 received both ft-om the White Sea and the Baltic, with 

 the eve side of a uniform blackish blue or plum-colour. 

 Shaw describes a PJeuronectes rosens" "of the most deli- 

 cate rose-colour, slightly tinged in some parts with 

 vellowish. and in others with silvery white.' This form 

 was taken in the Thames, and was without any spinous 

 warts or ctenoid scales. Bkown" tells us of a flesh- 



" Gen. Zoolog., vol. IV, P.sc. p. 302. Cf. Ii.w. 1. c. 

 '' Edinb. Joiirn. X.it. Geol. 11. p. 99, plate II. 



Scandinarinn Fithti. 



51 



