694 
SCANDINAVIAN FISHES. 
Fischer., Fischz. W '., 0. Prenss., p. 103. fig. 83; Grimm, 
Fish., Hunt. Russ. Wat., pp. 12 et 19; Apostol., Peche en 
Grece, p. 31; Norback, Handl. Fiskev., Fiskafv., p. 373; 
Bncke, Hanclb. Fischz., Fischer. (M. v. d. Borne), p. 142, 
fig. 150; Lillj., Sv., Norg. Fisk., vol. Ill, p. 358. 
The Sheatfish is the largest osseous fish in the fresh 
wafer of Europe. According to trustworthy verbal sta- 
tements" it attains in the south of Russia, in the Dnie- 
per, a length of at least 48 dm. and a weight of about 
295 kgm. Kramer (1756), quoted by Heckel and Kner., 
mentions a still larger Sheatfish from the Danube, “so 
large that two men could scarcely join hands round its 
body,” which thus might have measured between 6 and 
7 metres in length. The Sheatfish described by Osbeck 
(1. c.) was from Lake Bafven in Sodermanland and 
weighed 10 3 / 5 kgm. at a length of 1 1 1 / s dm. In Swe- 
den the species seldom attains a length of more than 
2Yg metres, though we sometimes hear of specimens 
half as long again h 
The form of the body reminds us strongly of the 
Burbot, with flattened head, terete trunk, and laterally 
compressed tail, though these three parts pass evenly 
into each other. Lithe as the Burbot — or even more 
so — and still more like the Eel in its movements, with 
loose and slippery skin, the body of the Sheatfish may 
assume different forms in different position; but when 
extended and at rest it presents the appearance given 
in our figure. The dorsal profile is almost straight, 
only slightly elevated at the end of the first quarter, 
where the dorsal fin is situated, from this point slightly 
curved towards the tip of the snout, and with a down- 
ward curve just behind this fin. The ventral profile is 
more regularly curved, more sharply ascending in front 
when the mouth is closed. The flat snout, the convex 
forehead, and the forepart of the back, which is also 
convex, but furnished at the middle with a more or less 
deep, longitudinal groove all the way from the occiput, 
are continued behind by the narrow, but terete dorsal 
edge of the tail. The ventral side, on the other hand, 
is indeed terete in front and along the belly itself more 
or less tumid; but behind the vent it is so sharp that 
the interhaemal spines (supporting bones) of the anal fin 
are even externally perceptible beneath the skin. The 
greatest depth of the body, which occurs at the dorsal 
fin, measures in young specimens, 2 or 3 dm. long, 
about 19 % of its length; while in older specimens 2 
metres long this percentage usually sinks to 13 c . The 
thickness at the same spot is in young specimens usually 
distinctly less than, in old specimens generally about 
equal to the depth. The least depth of the body, just 
in front of the caudal tin, measures in the said young 
specimens about 5 % of its length, in the older ones 
about 4 — 3 7 2 % thereof. 
The length of the head (from the tip of the snout 
to the extreme end of the branchiostegal membrane) 
measures 7s — Vis of that of the body (from the tip of 
the snout); but in old specimens the lower jaw projects 
in front of the tip of the snout for a distance that 
sometimes measures at least 1 / 9 of the length of the head. 
The broad, flat snout, with its sides sharply rounded 
(forming a broad ellipse) in front, passes very gradually 
into the terete form of the occiput and the forepart 
of the trunk, without any sharp lateral break, the 
head thus resembling a broad wedge with rounded sides. 
The breadth of the head across the opercula is the great- 
est breadth of the body (in old specimens about 14 % 
of the length of the body); but we are most struck by 
the great breadth of the gape, the width of which, 
measured straight across the corners of the mouth when 
closed, is about 4 / 5 of the greatest breadth of the head, 
and occupies almost the entire breadth of the snout. 
The lips are fleshy, the dermal folds at the corners of 
the mouth being especially thick. In young specimens 
the mouth shuts so tightly that the upper and lower 
lips are contiguous; but in older ones the lower jaw 
projects so far that a considerable portion of its card of 
teeth is left bare. The eyes are round and small, and 
sometimes even difficult to distinguish, as their colour 
differs only slightly from that of the head. Their rela- 
tive size varies considerably according to age. In spe- 
cimens between 1 and 2 dm. long the longitudinal dia- 
meter of the eyes measures about 10 % of the length 
of the head, 20 — 19 % of the breadth of the inte rorl iital 
space, or 30—27 % of the distance between them and 
the middle of the tip of the snout (the length of the 
snout). In specimens between 1 / 2 and 1 in. long these 
percentages have sunk, the first to about 6, the second 
to about 13 or 12, and the third to about 18 or 17. 
In a Sheatfish 19 dm. long (the original of our figure) 
the longitudinal diameter of the eyes was 5 % of the 
length of the head, only slightly more than 9 % of the 
a Kessler, Bull. Soc. Natur. Mosc., tom. XXIX (1856), I, p. 350. 
b On the lOlli of August, 1870, a Sheatfish 12 Sw. ft. (3 '/ 3 m.) long is said to have been brought to market at Eskilstuna. 
c In gravid females, or when the stomach is distended with food, the belly of course becomes both deeper and broader. 
