Ella Hoch in her 2013 article "Diagnosing fossilization in the Nordic Renaissance: an investigation into the correspondence of Ole Worm (1588–1654)", http://sp.lyellcollection.org/, quoted on page 320 a letter from Jan de Laët through Thomas Bartholin to Ole Worm in which De Laët said:... {"Meanwhile I have put into a box certain things whose names I have not found in your catalogue, and I shall hand it over to Mr Bartholin so that it will reach you more safely'. Among these things, continued de Lae¨t, were 'the skeleton of a hand and a rib of a sea monster that is common in the sea at the African coast near Angola. The Portuguese call it in their language Perxe de Moliher, which is the same as siren [sirenian, sea-cow]. And the pellets that are turned from the ribs are praised for being an excellent remedy against haemorrhoids, which I learned from an erudite Portuguese who had frequently experienced their effect'."}
  This animal was clearly an African manatee.