114 THE MAMMALS, REPTILES, AND FISHES OF ESSEX,
Clupea finta, Cuvier. Twait Shad.
This is occasionally common in the Colne. Many were
taken by the Smelt fishermen in August, 1886, and one was
caught on November 29th, 1886, at East Bridge, Colchester,
which point is the tidal limit. Jenyns says {Brit. Vert.
Animals, p. 438) it is very abundant in the Thames.
Family MURAENIDAE, Muller.
Genus Anguilla, Wittugh.
Anguilla vulgaris, Turton. Eel.
This fish is found in all our Essex rivers. Dr, Day, in his
work on The Fishes of Great Britain, so frequently quoted in
these pages, has conclusively shown that the numerous forms
of Sharp-nosed, Broad-nosed, and Snig-Eels are only varieties
of this species, which is the only Eel inhabiting fresh waters—
at least, for a part of its existence. It seems, at first sight, a
mystery how isolated pieces of water can have become stocked
by this fish ; but, if we remember that the " Elvers," or young
Eels, are always moving up stream, following even the smallest
trickling to its source, the explanation becomes comparatively
easy, since there are very few ponds that do not at some time
or other overflow, and the slightest stream is sufficient for
these tiny wanderers.
The well-known capability also of the larger Eels to wriggle
over considerable distances of land through wet grass or
other herbage must not be forgotten, although this, as far as
my experience goes, more frequently occurs when the pools
are drying up.
One instance, I remember, where the water in a large ditch,
forming part of the fence of a garden, had nearly evaporated.
By the help of a little dog, I caught in the grass several large
Eels, which were evidently on their way to the brook, some