This is J. R. Hind's symbol for the asteroid 18 Melpomene.
Hind, John Russell
1852
From <i>An astronomical vocabulary</i>, p. v. <a rel="nofollow" class="external autonumber" href="https://books.google.com/books?id=_DgDAAAAQAAJ&amp;pg=PR5">[1]</a>