746 
SCANDINAVIAN FISHES. 
The internal organs agree with the description given 
above of the structure of the Brachy enteric Cyprinoids. 
The stomach extends back to about a line with the in- 
sertions of the ventral tins, from which point the in- 
testine first runs forward, to the left of and above the 
stomach, until at the very front of the abdominal cavity 
it bends suddenly back to return straight to the vent. 
The entire length of the digestive canal is only about 
3 / 5 of the length of the body. The dorsal part of the 
musculature contains on each side an ellipsoidal organ 
of hitherto unexplained signification, proximally and 
dorsally attached to the fourth rib (the first of the nor- 
mal ribs). This organ is white and fairly large, being 
nearly 3 mm. long in a Gudgeon 110 mm. in length. 
It consists of transversely striped muscle fibres, exter- 
nally longitudinal, internally transversal, and is attached 
by connective tissue to the said rib. As for its mor- 
phological significance, Ave can find no better comparison 
than with the above-mentioned (p. 704) introitus cap- 
sules vesica in the Cobitoids. 
The Gudgeon has a wide geographical range to the 
east and west, from Amur and China" to England and 
Ireland. To the north and south its range extends in 
Europe from Southern Finland (Lat. 62° or 63° N.), the 
extreme south of Sweden, and Liim Fjord, to Central 
Italy. In Greece and Spain it is unknown. Its Swedish 
range consists principally of Scania, where it is fairly 
common in several localities. When Retzius in 1800 
introduced it into the fauna, of Sweden, it already pos- 
sessed at Lake Finja a special Swedish name, Slatting 
{slat — smooth). The species is also known to occur in 
Scania in Lake Vester and the Ronne River to the west, 
where according to Schagerstrom it is called Oral an- 
o 
ning, and in the streams of Helge and Arup to the east. 
From the River Morrum in Blekinge Baron G. C. Ce- 
derstrom in 1856 forwarded several specimens to the 
Royal Museum. The Zoological Museum of Upsala, 
according to Lilljeborg, has received specimens through 
Dr. Scheutz from the neighbourhood of Wexio. Accord- 
ing to Nilsson the Gudgeon also occurs in the River 
Nissa at Halmstad and is there called stensugare (Stone- 
sucker) * 6 . Krdyer did not know it from the Danish is- 
lands; but in recent times it has been found in Zealand 
(Feddersen). In Jutland it is common south of Liim 
Fjord. In Germany and the Baltic Provinces of Russia 
it is also common, as well as in Central and Western 
Europe. It is one of the inhabitants of the Cavern of 
Adelsberg. In the water-courses of Switzerland it ascends, 
according to Fatio, to a height of about 800 metres 
above the level of the sea; south of the Alps it is of 
rarer occurrence. 
The habits of the Gudgeon are fairly well expres- 
sed by its Swedish name of Sandkrypare (Sand-creeper). 
As it lies, usually in companies, close to the bottom, 
with the paired fins horizontally expanded, on a bed of 
sand, gravel, stone, or even of mud, it still keeps a 
careful watch, and by fits and starts displays great ac- 
tivity. It takes a, hook freely. It is fairly tenacious of 
life, but like all the Cyprinoids, sensitive to changes in 
the weather and incapable of enduring bad respiration. 
The living specimens in our aquaria kept close to the 
bottom and remained still in a packed mass, as long as 
the water was fresh; but as soon as it had stood an 
hour or so the crowd dispersed, and its members ascended 
severally to the upper layers of the water. In spite of 
this the Gudgeon can live in muddy or even polluted 
streams, and readily haunts the openings of sewers, 
provided they are in running water. 
Valenciennes" experimented on this fish in order 
to ascertain the effect produced on it by atmospheric 
rarefaction. The air-bladder became completely empty, 
its gas passed into the intestine, the belly swelled up, 
and the fish floated on its back, but Avas alive and 
seemed to steer its course in the Avater. After 24 hours’ 
continued operation of the air-pump he restored the 
fishes to a normal atmospheric pressure; and after the 
lapse of 6 hours they Avere quite recovered, Avith the 
air-bladder full almost exclusively of nitrogen. 
As Ave have remarked above, the comparatively 
short intestinal canal of the Gudgeon indicates that its 
food is chiefly animal. It lives principally on insects 
and their larvae, crustaceans, Avorms, and the roe and 
fry of various fishes; but it is fond of rooting up its 
food in sand and mud, and also devours decomposing 
substances, both animal and vegetable. 
The spaAvning-season of the Gudgeon occurs in 
Sweden at midsummer or earlier — in more southern 
countries even at the beginning of April. Before this 
time it has ascended from its winter-quarters to shal- 
loAver spots in rivers or brooks. In the River Hofdala, 
a Herzenstein and Warpachowsky, 1. c. 
6 Renewed attempts to procure the Gudgeon from this locality have, however, failed. 
c Cuv., Val., 1. c., p. 14. 
