COMMON DAB. 
387 
XII, p. 39 ; Benecke, Fisch ., Fischer., Fischz. 0. u. W. Preuss ., 
p. 95; Day, Fish. Gt. Brit., Irel., vol. II, p. 31, tab. CIV; 
Mela, Vert. Fenn., p. 308, tab. IX; Mob., Hcke, Fisch. 
Osts., p. 96; Lillj., Sv., Norg. Fn., Fisk., vol. II, p. 394. 
Pleuronectes platessoides, Faber, Fisch. Isl., p. 140. 
Limanda vulgaris, Gottsche, Wiegin. Arch. f. Naturg., vol. I, 
Bd. 2, p. 160; Mor., Hist. Nat. Poiss. Fr., tom. Ill, p. 289. 
Limanda oceanica , v. Bemm., in Herkl., Bouw. Fn. Nederl. 
Ill, p. 328. 
On the coasts of Scandinavia 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 tin; while in younger 
specimens, even when they have attained a length of 
6 cm., this proportion may be as low as 37 %. The 
length of the head is about V 4 — the variations run be- 
tween 23 and 27 % — of the distance between the tip 
of the snout and the base of the caudal tin; and the 
length of the caudal fin at the middle is from 17 to 
19 % of the total length of the body. 
The shape of the body is an unbroken oval, dis- 
tinguished from that of the preceding species of this 
genus by 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 of the head is even, with the exception of 
a marked depression at the eyes. 
In other respects the head deviates only 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 V 4 of the 
length of the orbit — and are of fairly equal size, the 
lower projecting slightly in front of the upper, which 
is set so high that part of it overtops the superior pro- 
file of the head. In the skull the length of the upper 
orbit measures less than 1 / 2 (about 44 %) of the distance 
between the head of the vomer and the occipital fora- 
men. The eyes themselves measure about 5 % b of the 
length of the body or 23 or 24 % c of the length of the 
head. In youth, as usual, the eyes are comparatively 
larger' 7 . The nostrils are of about the same form and 
position as in the preceding species; but even the pos- 
terior nostril of the eye side, where both 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 nostril of the blind side, with a 
fairly large dermal flap, lies a little in front of the per- 
pendicular from the anterior margin 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 jaw projects slightly in front of the 
upper. Its length is about the same as the least depth 
of the tail, about 8 or 9 % of the length of the body 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 pointed. 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 oq ~ 9g ’ 011 ^ ie 
.. 8—11 , 
eye side JvT “ On the latter side they are set ante- 
riorly, in the upper jaw for about 1 / 3 of the length of 
the mouth, in the lower jaw for about */ 3 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 ( Dve - 
panopsetta ), 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 
being 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 double". 
The position of the tins is normal, and the rays are 
scaly in the ordinary manner. The dorsal tin begins 
on the blind side, just behind the perpendicular from 
the anterior margin of the pupil of the upper eye, and 
a Couch {Hist. Fish. Brit. Isl., p. 185) mentions a specimen 33 cm. long, Day (Proc. Zool. Soc. London, 1885, p. 929) another 
38 cm. long. Mobius and Heincke state that the species may attain a length of 40 cm. 
6 According to Sundevall and Day sometimes 4. 
c According to Sundevall sometimes 22, according to Day sometimes 21. 
d 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. 
e It is probably this peculiarity that has given rise to the statement that the Flounders have 4 or 5 branchiostegal rays. 
