FLUKES. 
453 
EKSTROM’S TOPKNOT (sw. smaiivarfven). 
SCOPHTHALMUS NORYEGICUS. 
Plate XIX, fig. 1. 
Greatest depth of the body less than 40 %, total length of the head less than 25 %, length of the head behind 
the lower eye less than 14 % , maxillary bone of the eye side less than 10 %, maxillary bone of the blind side less 
than 9 %, branches of the lower jaw less than 12 %, pectoral fin of the blind side more than 8 %, base of the 
dorsal fin ( measured in a straight line) less than 75 %, its greatest height ( longest ray — 56tli — 59th ) less than 
11 %, base of the anal fin less than 65 %, its greatest height ( about the 43rd or 44tli ray) less than 11 %, the 
distance between it and the tip of the snout less than 23 %, length of the middle rays of the caudal fin more 
than 1 1 1 / 2 % } greatest thickness of the body more than 7 % — in each case relatively to the length of the body. 
Length of the pectoral fin of the blind, side more than i / 5 of that of the lower jaw on the same side , and the 
length of the middle caudal rays more than 1 / 3 greater than that of the lower jaw and also more than 1 / 2 the 
length of the head. Least depth of the tail more than 17 % of the greatest depth of the body. 
R. br. 7; D. 74 — 83; A. 63 — 68; P. sin. 10, dextr. 7 1. 8; 
V. 6; C. 2 + 12 + 2 1. 3 + 10 + 3; Lin. lat. 50 1. 51. 
Syn. Pleuronectes Uardina , Fr., Vet.-Akad. Handl. 1838, p. 184 
(excl. synon.) nec Guv.; Sundev., Skand. Fisk., ed. I, p. 200, 
tab. 50; Nilss. (Rhombus), Skand. Fn., Fisk., p. 643. 
Rhombus noruegicus , Gthr, Cat. Brit. Mus., Fish., vol. IV, 
p. 412; Coll. ( Zeugopterus ), Forh. Vid. Selsk. Christ. 1874, 
Tillfegsh., p. 139; ibid. ( Lepidorhombus ) 1879, No. 1, p. 77; 
N. Mag. Naturv. Christ., Bd. 29 (1884), p. 100; Malm 
(Rhombus), Gbgs, Boh. Fn., p. 518; Lillj. (Zeugopterus), 
Sv., Norg. Fiskar, II, p. 336. 
Ekstrom's Topknot, Couch, Fish. Brit. Isl., vol. Ill, p. 175, 
tab. CLXVII. 
Obs. Cuvier’s Pleuronectes (Rhombus) Cardina is clearly a 
combination of Scophthalmus , to which he refers in his quotation of 
Duhamel (7>. Peches , sect. IX, pi. VI, fig. 5), and Lepidorhombus 
whiff, as shown by his quotation of Ray (Syn. Pise., p. 163, pi. 1, 
No. 2). Fries, too, regarded Scophthalmus norvegicus as identical 
with Sc. unimaculatus (Bloch’s Topknot). 
Ekstrom’s Topknot fully deserves the Swedish name 
(= Small Fluke) given it by Fries and Sundevall. Its 
maximum length is apparently about 12 cm. The 
largest specimen ever found in Scandinavia was 117 
mm. long. Thus, to the best of our . knowledge at 
present, it is the smallest Scandinavian Flatfish. The 
body is of a regular oblong shape, elliptical but elon- 
gated and narrow at the head and tail. The greatest 
depth, which increases even relatively with age, varies 
between 31 j‘ 2 and 37 Vg % of the total length of the 
body, or between 37 and 45 % of the length of the 
body minus the caudal fin. The snout forms a slightly 
rounded angle of somewhat less than 90°. At the 
upper eye there is a slight depression in the profile 
of the head (see the preceding species), but the lower 
jaw, with its feebly marked chin, projects beyond the 
ellipse in a rectilinear, obtuse angle. Behind the ter- 
minations of the dorsal and anal fins the tail forms a 
section of uniform depth, measuring about 1 / 5 (18 — 23 %) 
of the greatest depth of the body, and almost as long 
as it is deep, this being one of the most prominent 
distinctions between this species and the Whiff. 
The length of the head is between 23V 2 and 22 x / 2 % 
of the total length of the body, or between 2 8 7a and 
26 1 / 2 % of the length of the body to the base of the caudal 
fin. Its external form we have just described. The 
eyes are set close together on the left side. They are 
oblong and very prominent, the upper being somewhat 
larger than the lower, and situated a little behind it, 
close to the depression in the upper profile of the head. 
The lower eye is set close to the margin of the jaw. 
The iris and pupil are simple, of normal shape, and 
without any intruding lobe from the former into the 
latter. The narrow and terete interorbital space (the 
projecting ridge between the eyes) forms a carina, which 
follows the curve of the margin of the lower eye from 
the middle of the side of the upper jaw, and then 
coasts the margin of the upper eye, vanishing behind 
this point. The nostrils resemble those of the rest of 
the Bothoids: the openings are small, a little way apart, 
with high, soft margin, which in the anterior nostril 
is tubular and obliquely truncate, and behind elongated 
