LECTURE XL 
185 
often n ith a cast of flesh-colour ; and is composed 
of about five valves ; the two on each side being 
largest, and the fifth or back valve being slender 
or narrow. From the front of the shell hang out 
the curved tentacula, of a somewhat dusky colour, 
and resembling the shape of a plume of feathers. 
Among the numerous errors with which Natural 
History was formerly encumbered, there prevailed 
an idea that the Bird called the Barnacle goose 
was not produced like other birds, from an egg, 
but that it derived its origin from this shell. This 
error, gross and absurd as it was, seems to have 
met with credit from authors who should have 
viewed objects of this nature with other eyes than 
those of the vulgar. It was supposed by these phi- 
losophers that the inhabitant of this shell was an 
immature bird, or young of the above-mentioned 
goose, which, after having attained its plumage, li- 
berated itself from the confinement of its shell, and 
dropped into the water. The numerous tentacula 
or arms of the inhabiting animal, which are disposed 
in a semicircular form, and, as before observed, 
have a feathery appearance, seem to have been 
all that could reasonably be alleged in favour of 
this strange supposition. Among others who have 
