Sorry, I forgot to include this in the former message (to make it shell
related):
About 'Clithon squarrosa':
I doubt about typographic mistake as the clue, because there is also a
'Trochus squarrosa' Lamarck, 1822 and a 'Aegista squarrosa' Gould, 1859 ...
or maybe typographs are very negligent.