_Barnacles in the River Thames._--In Porta's _Natural Magic_, Eng. trans.,
Lond. 1658, occurs the following curious passage:
"Late writers report that not only in Scotland, but also in the river
of Thames by London, there is a kind of shell-fish in a two-leaved
shell, that hath a foot full of plaits and wrinkles: these fish are
little, round, and outwardly white, smooth and beetle-shelled like an
almond shell; inwardly they are great bellied, bred as it were of moss
and mud; they commonly stick in the keel of some old ship. Some say
they come of worms, some of the boughs of trees which fall into the
sea; if any of them be cast upon shore they die, but they which are
swallowed still into the sea, live and get out of their shells, and
grow to be ducks or such like birds(!)."
It would be curious to know what could give rise to such an absurd belief.