PREJUDICES OF SENSE. 161 
anatomical structure; and we are at last compelled 
to believe that the fact before us, although true, is 
contrary to the usual course of nature. 
(100.) Prejudices of sense show themselves in va- 
rious ways. A recent author, who writes upon shells, 
finding a new genus of barnacle, occupying the de- 
serted holes of some perforating bivalve*, concludes 
that the excavations have been made by the barnacle. 
and therefore names it Lithotrya! There is nothing 
surprising or reprehensible in this, for it is an error 
which all who trust alone to their eyesight would 
most assuredly have fallen into. On looking further 
into the matter, however, and ascertaining the gene- 
ral structure of this group of animals, so admirably 
illustrated by Polit, we see the physical impossi- 
bility of their possessing this perforating power; 
and it is known, moreover, that barnacles, instead of — 
being shell-fish, are articulated Annulose, and belong 
to the class of Insects.{ The origin of the genus 
Gionea has recently been quoted by one of the most 
eminent mathematicians of the age§, as an example 
of fraudulent hoaxing ; although, I confess, it ap- 
pears to me more allied to the subject now touched 
upon. M. Gioeni finds, upon the coasts of Sicily, 
the hard internal parts of a shell-fish (Bulla 
lignarea L.); and this object, more resembling a 
bivalve than any thing’ else, he mistakes for the 
shell itself, and publishes it as such. The cele- 

* Cuvier, Rég. Animal, 2d ed. vol. iii. p. 177. 
+ Testaceze Utrinque Sicilie, vol. i. pl. 4, 5, 6. 
$ See also Thompson’s Zool. Researches, No. 3. 
§ Babbage on the Decline of Science, p. 175. 
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