COMMON' DAB. 



387 



XII, p. 39; Benecke, Fiseh., Fischer., Fiscln. 0. u. W. Preuss., 



p. 95; Day, Fish. Gt. Brit., IreL, vol. II, p. 31, tab. CIV; 



Mela, Vert. Fenn., p. 308, tab. IX; M6r., Hcke, Fisch. 



Osts., p. 915; L11.1.J., At'., Nonj. Fn., Fink., vol. II, p. 394. 

 rieuronecte.^ platessoides, Fabei!, Fisch. IsL, p. 140. 

 lAmanda vtilgnris, Gottsche, Wiegin. Arcli. f. Natiirg-., vol. I, 



Bd. 2, p. 100; MoR., Hist. Nat. Poiss. Fr., toiu. HI, p. 289. 



Limanda ocerniica, 

 III, p. 328. 



V. Bemji., in Herki... Dotur. Fn. NcderL 



On the coasts of Soandinavia the usual length of 

 the Dab is between 24 and 28 cm., and scarcely ever 

 more than 30 cm." The greatest depth of the body in 

 full-grown specimens, more than 15 cm. long, varies be- 

 tween about 45 and 51 % of the length from the tip of 

 the snout to the base of the caudal fin; while in younger 

 specimens, even when they have attained a length of 



6 cm., this proportion may be as low as ?>1 %. The 

 length of the head is about ' ,, — the variations run be- 

 tween 23 and Tl % — of the distance between the tip 

 of the snout and the base of the caudal fin; and the 

 length of the caudal fin at the middle is from 17 to 

 19 ?o of the total length of the body. 



The shape of the body is an unbroken o\al, dis- 

 tinguished from that of the preceding species of this 

 genus l)y the circumstance that the tail is attenuated 

 behind the greatest depth of the body rather more 

 sharply and to a greater length. The body is deepest 

 a little behind the end of its first third, at about the 

 28th, 29th or 30th ray of the dorsal fin. The curves 

 of the upper and lower contours are alike, and even 

 the profile (jf the head is even, with the exception of 

 a marked depression at the eyes. 



In other respects the head deviates onlj- slightly from 

 the structure it possesses in the preceding and following 

 species. Its greatest thickness, which is generally the 

 greatest thickness of the body as well, measures about 



7 or 8 % of the length of the body or about 35— 42 % 

 of its own length. The eyes are set fairly close to- 

 gether — the external breadth of the flat ridge between 

 them, at its narrowest part, measuring about "^ of the 

 length of the orl)it ■ — -and are of fairly equal size, the 

 lower |)rojecting slightly in front of the upper, which 

 is set so high th.at part of it overtops the superior pro- 

 file of the head. In the skull the length of the upper 

 orbit measures less than ^'j (about 44%) of the distance 



between tlie iiead of the vomer and tin' occipital fora- 

 men. The eyes themselves measure about 5 %'' of the 

 length of the body or 23 or 24%' of the length of the 

 iiead. In youth, as usual, the eyes are comparatively 

 larger'. The nostrils ai'e of about the same form and 

 position as in the preceding species; but even the pos- 

 terior nosti'il of the eye side, Avhere botii nostrils lie 

 in front of the perpendicular from the anterior margin 

 of the eyes, has its margin somewhat raised in a tubular 

 form. The anterior nosti'il of the blind side, with a 

 fairly large dermal tiaji, lies a little in front of the per- 

 l)endicular from the anterior mai'gin of the upper eye, 

 the posterior, without any elevation of the margin, just 

 behind this perpendicular. The mouth is small, the 

 maxillary bone of the eye side scarcely extending back 

 to the perpendicular from the anterior margin of the 

 pupil. The lower jaAv projects slightl}- in front of the 

 upper. Its length is about the same as the least depth 

 of the tail, alxjut 8 or 9 % of the length of the bodj' or 

 40 — 43 % of the length of the head. The teeth are some- 

 what conical, in the lower jaw blunt, and in the upper 

 jaw more j)ointed. They are set in a single row, which 

 is often irregular, at intervals less than the breadth of a 



20-24 



tooth. Their number on the blind side is ^ 

 8—11 



„ on the 



20—23' 

 eye side y-^ — r^. On the latter side they are set ante- 

 riorly, in the upper jaw for about Vs of the length of 

 the mouth, in the lower jaw for about ^/j or sometimes 

 the whole of the length of the mouth, to a line with its 

 inner corner. The branchiostegal membrane, as in all 

 the Scandinavian Flatfishes except the Rough Dab {JDre- 

 IMnofsetta), is furnished with 6 larger rays on each side 

 and 2 smaller ones at the middle. The 6 large rays 

 are distant from the middle and only slightly flattened; 

 but they are not always distinct or easy to count, this 

 beino: due to the fact that the membrane does not lie 

 flat, with the margin behind, as in other fishes, but is 

 folded back, in this species and most of the others, to half 

 the breadth of the membrane, which thus lies doul)le''. 

 The position of the fins is normal, and the rays are 

 scaly in the ordinary manner. The dorsal fin begins 

 on the blind side, just behind the perpendicular from 

 the anterior margin of the pupil of the upper eye, and 



« Couch {Hist. Fish. Brit. IsL, p. 185) mentions a specimen 33 cm. long. 1>av (Proc. Zool. Soc. London, 1885, p. 929) another 

 38 cm. long. Mubius and Heixcke state that the species may attain a length of 40 cm. 

 * According to Sun'devai.l and Day sometimes 4. 



<■ According to Sundevali. sometimes 22, according to Day sometimes 21. 



'' In specimens about 6 cm. long the longitudinal diameter of the eye is about 6 °„ of the length of the body or 27 '<. of the length of the head. 

 ' It is probably this peculiarity that has given rise to the statement that the Fiounders have 4 or 5 branchiostegal rays. 



