Whilst they are still alive and before they are washed and
cleaned, they are blackish in colour. Their attachment is not made
at one particular spot, nor is it made all over their bodies; for
vacant pore-spaces intervene. There is a kind of membrane stretched
over the under parts; and in the under parts the points of
attachment are the more numerous. On the top most of the pores are
closed, but four or five are open and visible; and we are told by some
that it is through these pores that the animal takes its food.